The Polish lorry driver whose vehicle was hijacked and used in the attack – claimed by the Islamic State of Iraq and the Levant (Isil) – was being hailed a hero after police said it was possible he sacrificed his life to cut short the carnage
Yet more pressure was piled on Angela Merkel, the German chancellor, who was already facing criticism from opponents and supporters alike over her “open door” refugee policy that allowed migrants into the country without vetting
Two Britons were treated for shock and minor injuries after being caught in the Christmas market attack.
On Wednesday night, Mrs Merkel was receiving regular updates on the huge manhunt for Amri, whose name was found on documents under the driver’s seat in the cab of the lorry used in the attack.
The hunt spread across the borderless Schengen zone, with police conceding that the suspect could have travelled hundreds of miles since Monday night’s outrage.
His brother Abdelkader Amri said from his home in Tunisia: “When I saw the picture of my brother in the media, I couldn’t believe my eyes. I’m in shock, and can’t believe it’s him who committed this crime. If he’s guilty, he deserves every condemnation. We reject terrorism and terrorists – we have no dealings with terrorists.”
Police are believed to have found Amri’s blood in the lorry’s cab. They now assume that whoever was driving the lorry was badly injured, either when pieces of wood smashed through the windscreen or in a fight with Lucasz Urban, the Polish driver.
Squads of officers have been to every hospital in Berlin and the surrounding state of Brandenburg trying to ascertain if the killer was treated in any of them.
Mr Urban’s injuries suggested he may have been alive as the lorry ploughed into Christmas shoppers, having perhaps been assumed dead by the hijacker who had stabbed and beaten him.
It gave rise to the theory that he grabbed the steering wheel, forcing the lorry off its intended course through the middle of the crowd and potentially saving countless lives. His life came to an end when he was shot in the head by the hijacker.
Mr Urban’s family said he would have fought “to the end”, while a security source said his bloodied and swollen face meant “there must have been a fight”.
Police hunting for Amri are believed to be focusing their search in North Rhine-Westphalia, the industrial area of Germany that borders the Netherlands and Belgium where he had been living when he came under investigation this year.
Prosecutors in Berlin said he was placed under surveillance on March 14 following a tip-off that he might be planning a robbery to finance the purchase of automatic weapons for use in a terrorist attack.
He was observed dealing drugs in a Berlin park and fighting in a bar, but the surveillance was called off in September. Another report suggested his mobile phone was still being monitored but that he went underground earlier this month and police lost track of him.
Amri was arrested in August with a false Italian identity document, but released shortly afterwards. Other sources suggested his arrest was in connection with a grievous bodily harm case.
He had lived in Berlin for most of his stay in Germany, but recently moved back to refugee accommodation in Emmerich, near the Dutch border, which was raided by police yesterday. His family were also being questioned by investigators in Tunisia.
Amri lived with a flatmate who was arrested last month on suspicion of recruiting volunteers to travel to Syria to fight for Isil. The flatmate was one of several men arrested simultaneously, including an extremist preacher called Abu Walaa, known as “the faceless preacher” because he refused to face the camera in videos.
The suspect is believed to have been in contact with Walaa, one of the few extremist preachers in Germany openly to declare his support for Isil, and the group of arrested men.
In another disclosure that raises questions about the police investigation, it was revealed that the Pakistani asylum seeker initially held as a suspect was targeted because he accidentally jumped a red light.
Naved Baluch, 23, who arrived in Germany a year ago, was seized after witnesses saw him commit a traffic offence a mile away from the crime scene. Detectives who flew him out of Berlin and across the country to Karlsruhe to question him, took 18 hours to release Mr Baluch, who had no blood on his clothes and no injuries.
It was only then the security services warned the public that the real killer was on the run with a gun. “We declared victory too soon,” said one investigator.
David Videcette, a former Scotland Yard counter terrorism officer who worked on the London 7/7 investigation, said Britain was better at preventing plots because there was better collaboration between the police and security services and they had learnt the lessons of the past.
He said: “After the 7/7 bomb attacks and particularly the 21/7 incident when Jean Charles de Menezes was shot, the UK took a very close look at the way everything operated.
“Prior to that, you had the Security Service on one side, the police on the other and Special Branch in the middle deciding what information was being passed between the two. After the attacks on London it was recognised that this relationship was not working and things were going wrong. Now the police and Security Service talk to one another and share information and that is one of the reasons we are successful in stopping plots.
“In Germany however, in common with other mainland European countries, they are a long way behind. There are numerous agencies operating in the same space and this creates problems. Information is not shared and things get missed.”
Germany’s strict privacy laws initially prevented pictures of Amri being published there, or even his surname. Instead media outlets in the country had to obscure his eyes in photographs and call him Anis A until the authorities decided to publish an unredacted wanted notice describing him as “highly dangerous”.
State surveillance is a sensitive issue in Germany because of extensive snooping by the Stasi secret police in Communist East Germany and by the Gestapo in the Nazi era.
However, on Wednesday a bill was passed to allow more video surveillance in German society with greater weight given to “the protection of life, health and freedom”.
As dramatic accounts of near-escapes by survivors of the attack continued to emerge, an Italian man said he “looked death in the face” and it was a “miracle” he and his wife survived.
Giuseppe La Grassa, 34, was on holiday celebrating his wedding anniversary and his birthday and described how close his wife Elisabetta came to being killed.
He said: “It is miracle my wife is alive. She was about to go and get a sandwich, but then she delayed a moment and was passed by a girl. The girl was killed, run down by the lorry.”
It said: “This is Berlin. We are Berlin. We ride the S-Bahn in the rush hour. We complain when people are friendly to us. Our taxi drivers are more dangerous than any converts... and we love our children like crazy, even if they are lactose-intolerant. Whatever that is. We have nine months of winter and we go straight to work from partying. Some of us are Turks. Or Russians. Or Americans. Pakistanis too. Scared of you?! Dream on.”
BBC security correspondent Frank Gardner has told the News Channel that the encounter with Anis Amri was "probably more than luck".
"Italy was on alert for this guy, he had spent four years in Italy mostly in jail, and he was known already to the Italian authorities," he said.
"He probably made a mistake going back to Italy, he would have been probably trying to hide himself in the suburbs or indeed trying to get himself over to Syria.
Railway tickets found on Amri's body showed he had travelled from Chambery in south-eastern France to Turin and then on to Milan, Italy's Ansa news agency says.
'It's all too convenient': Questions over how police missed Berlin attack suspect's ID in truck for 24 hours - as it emerges far-right leader 'KNEW attacker was a Tunisian Muslim' hours after the atrocity
A far-right leader in Germany knew the suspect in the Christmas market attack was a Tunisian just two hours after the attack - despite police initially arresting a Pakistani man, it has emerged.
Lutz Bachmann, who fronts the anti-immigrant PEGIDA group, tweeted on Monday night that he had 'internal police information' about the nationality of the lorry driver who murdered 12 revellers in Berlin.
At the time, police had announced the arrest of a Pakistani asylum seeker - it was only when he was released that Tunisian Anis Amri was publicly identified as the chief suspect.
It comes as conspiracy theories surfaced online questioning how police missed the suspect's ID in the truck for 24 hours.
A far-right leader in Germany knew the suspect in the Christmas market attack was a Tunisian just two hours after the attack - despite police initially arresting a Pakistani man, it has emerged
At the time, police had announced that their chief suspect was a Pakistani asylum seeker - it was only when he was released that they turned their attention to Tunisian Anis Amri
Lutz Bachmann, who fronts the anti-immigrant PEGIDA group, tweeted on Monday night that he had 'internal police information' about the nationality of the lorry driver who murdered 12 revellers in Berlin
When asked to explain how he knew this information, he wrote in a follow-up tweet: 'Just need the right connections and a whistleblower that is sick of the lies.'
Controversial Bachmann tweeted his information on Monday night - before police officially confirmed that they were hunting a Tunisian suspect.
Meanwhile, conspiracy theorists have questioned the 'suspicious' discovery of the Berlin attack suspect's wallet in the lorry used to murder 12 people at a packed Christmas market.
German police named Anis Amri as the chief suspect in the attack after finding his ID - apparently abandoned by the asylum seeker in the footwell of the truck as he fled the scene.
Investigative reports: Berlin truck attack story: German counter-terrorism police tie themselves in knots - Turkish 'off duty policeman' Mevlut Mert Altintas assassinates Russian ambassador Andrei Karlov. Lorry crashing into Christmas Market in Berlin – Anis Amri is named as perpetrator after police find his ID documents in lorry!: why did police not name him straight away - seeing as they knew according to Pegida; was this a NATO intelligence false flag operation? – examples of these from history; CCTV now being rolled out in German cities for the first time; ISIS terror cell in Samur, France exposed as 'government military exercise'; 7/7 London bombings; GLADIO A, B. and C; ITV news report on Anis Amri by Rohit Catchri – grilling Steinmeyer; Scania lorry hacked? Slaying of Russian ambassador Andrey Karlov in Ankara by Mevlut Mert Altintas - an off duty policeman and Gulan supporter: CIA involvement?; he recited an Al Nusra of Syria anthem. Egyptian police arrest five people for using children to fake 'Aleppo' footage – Bell Pottinger paid hundreds of millions of dollars by the Pentagon to create fake footage to use on social media and the news. Western intelligence officers arrested in eastern Aleppo. UK 'secretly selling arms to Saudi Arabia and elsewhere under opaque licencing system'. Turkish air raids kill 47 civilians in Syria's al-Bab. US Army deploys tanks to Europe ratcheting up tensions with Russia. Trump's phone call to US media on 9/11 saying how Twin Towers were very strong and bombs must have been involved too. Why did satellite TV rolling news channel RT drop our hard-working presenter Tony Gosling? His penultimate interview about Litvinenko and his book 'Blowing up Russia' may explain why – this is about false flag bombings in Russia to stop the Communists getting into power – history of Putin's rise to power, Shamil Basayev and the central involvement of Boris Berezovsky. Space War: clip from film 'War in Space – the next battlefield' by CNN versus clip from film 'Pax Americana - The Weaponisation of Space' – more money spent on space war now but there is less of a threat - Nazi space weapons engineer/designer Wernher von Braun; Cyber attacks and smart meters – how do we know who's done it? The satelllite killers: US making all the running in cyber and space warfare.
'....Just one day later, the Berliner Morgenpost and RBB published the results of their research. This is based on internal investigations and statements by the co-defendants’ attorneys in the Abu Walaa trial. The charges against Abu Walaa and other suspected Islamists in further terrorist trials are mainly based on the statements of the undercover state agent.
Most of the group members had wanted to leave for Syria to fight on the side of Islamic State (IS). They had not spoken about attacks in Germany. Agent “Murat” had several times said to members of the group: “Come on, you don’t have a passport anyway, do something here, carry out an attack.”
In a police interrogation in December last year, a former supporter of an Islamist group had already warned about a man named “Murat.” He was “extremely radical,” the witness said, according to information from those close to the investigation. “Murat” had also repeatedly said that one needed good men “who are able to carry out attacks.”
In a further interrogation, the witness is reported to have said that “Murat” wanted to talk more about Kalashnikovs than about prayers. When he saw youngsters and parents in a meadow, he said “they had to be killed because they denied God.”
A former supporter of the Abu Walaa group told RBB that “Murat” was “the most radical.” A former member of the Islamist scene—it is unclear whether it is the same man—reaffirmed to RBB reporters that “Murat” had prompted him to carry out attacks: “I can testify 100 percent that he also tried to do this with me.”
Several lawyers confirm the allegations. “My client has reported to me that VP-01 talked to him about possible attack locations and gave him the tip to shave off his beard so that he attracted less attention,” the Düsseldorf defence lawyer Johannes Pausch said. His client was sentenced to imprisonment for planning an attack. “Murat” had not sought to slow down his client, who was then a minor, but had “insisted” he act, he said.....'
Aurora also known as SR-91 Aurora is the popular name for a hypothesized American reconnaissance aircraft, believed by some to be capable of hypersonic flight at speeds of Mach 5+. According to the hypothesis, Aurora was developed in the 1980s or 1990s as a replacement for the aging and expensive SR-71 Blackbird.
A British Ministry of Defence report released in May 2006 refers to USAF priority plans to produce a Mach 4-6 highly supersonic vehicle, but no conclusive evidence had emerged to confirm the existence of such a project. It was believed by some that the Aurora project was canceled due to a shift from spy-planes to high-tech unmanned aerial vehicles and reconnaissance satellites which can do the same job as a spyplane, but with less risk of casualties.
The main question here is, Does the US Air Force or America’s intelligence agencies have a secret hypersonic aircraft capable of a Mach 6 performance?. The continually growing evidence suggests that the answer to this question is YES. Perhaps the most well-known instance which provides evidence of such an aircraft’s existence is the sighting of a triangular plane over the North Sea in August 1989 by oil-exploration engineer Chris Gibson. As well as the famous “skyquakes” heard over Los Angeles since the early 1990s, found to be heading for the secret Groom Lake (Area 51) installation in the Nevada desert, numerous other facts provide an understanding of how the aircraft’s technology works. Rumored to exist but routinely denied by U.S. officials, the name of this aircraft is Aurora.
The outside world uses the name Aurora because a censor’s slip let it appear below the SR-71 Blackbird and U-2 in the 1985 Pentagon budget request. Even if this was the actual name of the project, it would have by now been changed after being compromised in such a manner.
The plane’s real name has been kept a secret along with its existence. This is not unfamiliar though, the F-117a stealth fighter was kept a secret for over ten years after its first pre-production test flight. The project is what is technically known as a Special Access Program (SAP). More often, such projects are referred to as “black programs.”
So what was the first sign of the existence of SR-91 Aurora ? On 6 March 1990, one of the United States Air Force’s Lockheed SR-71 Blackbird spyplanes shattered the official air speed record from Los Angeles to Washington’s Dulles Airport. There, a brief ceremony marked the end of the SR-71’s operational career. Officially, the SR-71 was being retired to save the $200-$300 million a year it cost to operate the fleet. Some reporters were told the plane had been made redundant by sophisticated spy satellites.
Soaring at 5,000 miles per hour through the night sky these unidentified flying objects could be a 21st century addition to NATO's airforce. Radar stations at Prestwick, West Freugh and RAF Buchan may have tracked their movements as they fly between secret airbases and the Norwegian Fjords, but the Ministry of Defence and the US Air Force deny they even exist.
ALMOST invisible to radar, the F-117 Stealth fighter is one of the most sophisticated warplanes ever built.
But for seven years the US Government denied that the top- secret aircraft - nicknamed Nighthawk - existed.
Ranging the night skies over Baghdad on 1,270 missions the Nighthawks struck the most heavily defended Iraqi targets to stunning effect.
Now from the cloak of X-Files denial comes a Stealth successor: more powerful, blacker, faster and even more secret.
Under the codename Project Aurora - which may be a wrap for several secret aircraft - the planes are classified within the US defence department's black programme - one whose existence is not admitted by the authorities.
Experts claim experimental and prototype Aurora aircraft are using Scotland, the skies above the North Sea and the wilderness areas of far-Northern Europe as their testing ground.
Bill Sweetman, former technical editor for Jane's Information Group and an author of three books on Stealth technology claims the areas are ideal proving ranges.
He claims that after 17 years the US defence department is reaching the latter stages of trialing space-age military aircraft capable of astonishing speeds.
"There continues to be a huge black hole in what we know the Pentagon has spent money on," he told the Press and Journal.
"In 1999 black projects accounted for $12.1 billion of USAF research expenditure - that is almost 40% of the $32 billion research and development budget."
Advanced secret aircraft developed at highly classified Government facilities in the Nevada Desert almost certainly include both manned and unmanned hypersonic jets designed to perform strategic reconnaissance and other less conventional missions for the US Air Force and its NATO allies.
A number of these aircraft have been seen and heard by ground- based and airborne observers in the western USA and in northern Europe during the past 10 years.
Based on more than 60 eye-witness reports there appears to be at least three distinct types of vehicle:
One is a "triangular-shaped quiet aircraft" observed with a fleet of Stealth fighters several times between 1989 and 1995. This may be a demonstrator or prototype of the much vaunted McDonnell Douglas A-12.
Another is a high speed aeroplane characterised by a very loud, deep rumbling roar, reminiscent of heavy-lift space rockets. In flight it makes a pulsing sound and leaves a segmented vapour trail.
The final contender is a high altitude jet that crosses the night sky at extremely high speed and at altitudes in excess of 50,000 feet. It is usually observed as single bright light but no engine noise or sonic boom is heard.
In one seven month period a small team of observers in California logged at least 30 sonic booms believed to be produced by the same unknown aircraft.
Claims have surfaced that booms from Aurora test flights are responsible for sudden avalanches in Norway and an earthquake in the Netherlands as well as unexplained radar blips, eerie noises and isolated UFO sightings in Scotland.
Reporters from Norwegian newspaper Aftenposten say they have received numerous complaints of sudden bass-like booms from isolated fishing communities and farmsteads between Trondheim and Narvik, followed by sudden avalanches of snow.
They say that recently released information suggests that a 1986 avalanche in the Troms area of northern Norway, which killed 16 NATO soldiers, may have been triggered by early tests of a secret supersonic jet.
The P and J understands that Norwegian Government officials are now concerned about Aurora flights, damage caused by sonic booms and the lack of consultation from their US NATO allies.
An Oslo-based Government spokesman said they were carrying out long-standing research into the causes of avalanches and they were aware of the concern over test flights by military aircraft from the UK.
"We always receive a number of complaints from people over low- flying aircraft and sonic booms - and it is probably true that some sonic booms cause avalanches," he added.
Dutch scientists have meanwhile blamed the secret jet for causing a sudden earth tremor which jolted the north coast of the Netherlands.
A North-east RAF base recently traced a very fast radar blip across the North Sea. But when the incident was reported to RAF Buchan, superior officers denied all knowledge of it.
Oceanic Air Traffic Control at Prestwick also tracked fast- moving radar blips. It was claimed by staff that a "hypersonic jet was the only rational conclusion" for the readings.
Experts claim the Aurora has probably flown out of RAF Machrihanish airfield in Argyll while hi-tech tracking equipment at Benbecula, RAE West Freugh in Galloway and Fylingdales monitor its progress.
There have been reports of unidentified night-time aircraft noises from Machrihanish for a number of years.
But with the Kintyre base now downgraded to a care and maintenance position, experts are puzzled about the location of the Aurora's new European test base.
"The information currently available shows Scotland and the North Sea are used extensively for the testing of these aircraft," he said.
Mr Hickling, who for nine years covered science and manned space for the Gannet Newspapers Washington bureau, added: "I believe it is extremely likely that the aircraft - test beds for hypersonic engine and control technology - would be unmanned, because human bodies could not stand the G forces generated by manoeuvres at hypersonic speed."
But last night Bill Sweetman said high speed - such as at Mach 7 or 8 - would not exclude manned aircraft. "It is only when you manoeuvre an aircraft at that speed that G forces come into play," he said.
Mr Sweetman said the development of the Aurora within the US defence department's "black projects" was a natural progression from the Stealth fighter, which first flew in 1982.
"The evidence is strong that high speed propulsion and aerodynamics are at the cutting edge of this new development and the long runways at Groom Lake (USA) and Machrihanish would be ideal to fly the plane from."
He said the skeleton staff at the "care and maintenance" RAF Machrihanish would be a perfect cover for further trialing of Aurora aircraft.
"One of the missions of high altitude supersonic aircraft was to operate over the North Atlantic as a reconnaissance strike system against the Soviet Northern Fleet and it would be natural to continue that test range despite the end of the cold war."
The ultimate in aerodynamics the aircraft could reach anywhere in the world in three hours, he claimed.
However an MoD spokesman said last night: "There are no United States Air Force prototype aircraft based at British airbases and no authorisation has been given by Her Majesty's Government to the USAF - or any other US body - to operate such aircraft within or from the United Kingdom.
A spokesman for the US defence department denied any knowledge of Aurora or "Deep Black" aircraft. Mr Sweetman said it was natural for British and US military spokesman to deny the existence of the plane.
"Put it this way," he said, "In 1988 the US Air Force had 50 F- 117 Stealth aircraft operating in Nevada and still denied they existed."
So secret, its existence is not even acknowledged: Futuristic 'Aurora' spy plane that travels at SIX TIMES the speed of sound is blamed for mysterious booms heard at the weekend
The top-secret Aurora project was first first reported on in 1989 and it could be behind Lockheed Martin's SR-72 plane concept
The origin of the mysterious bangs heard across the UK and New York at the weekend are yet to be officially identified.
But a leading theory is that they were created by an aircraft possibly travelling at supersonic or hypersonic speeds above the Atlantic.
This has led conspiracy theorists to attribute the booms to a spy plane rumoured to be under development by the US military, under the codename Aurora.
Theory: Aurora is rumoured to be a top secret aircraft in development since 1989. Last year Lockheed Martin announced it was developing a similar SR-72 spy plane (illustrated) said to be able to accelerate up to Mach 6	+8
Aurora is rumoured to be a top secret aircraft that has been in development since 1989. These claims originated in Aviation Week and Space Technology magazine in 1989. In November 2013, Lockheed Martin announced it was developing a similar SR-72 spy plane (illustrated) said to be able to accelerate up to Mach 6
Dr Bhupendra Khandelwal, an engineering research associate from Sheffield, claims the loud bangs were created by a type of experimental jet engine called a pulse detonation engine.
Claudia Angiletta, a resident from Croydon, South London, recorded the sounds as she was watching TV at home at around 10pm GMT on Saturday.
Within minutes, Twitter users had started spreading hashtags - from the straightforward #loudbangs to the somewhat melodramatic #omgwereallgoingtodie.
At around the same time, residents in locations including Buffalo, Cheektowaga, Clarence and as far north as Niagara Falls on the east coast of the US also took to social media to report the unusual noises.
It's conceivable that with that sort of power, speed, and altitude, the sound would carry over a vast distance. #hypersonic #loudbangs
The continuous noise and odd sound it makes would then be explained by reverberations around the stratosphere. #loudbang #hypersonic
It seems to me that everyone has ruled out sonic booms, no one is considering hypersonic booms, both US & China developing it #loudbangs
Twitter user Brailsford believes the noises were created by hypersonic booms (tweets pictured above). He added that the continuous and odd sound could be explained by reverberations around the stratosphere
Could it be? An artist's image of the so-called Aurora project. Enthusiasts say one possible power source is a 'pulse detonation engine', whose sound is said to resemble that caught on an audio clip on Saturday	+8
Enthusiasts claim that such a supersonic or hypersonic plans could be what caused the strange noises at the weekend. In particular, an expert said the sound is similar to that created by pulse detonation engines. An artist's illustration of what the Aurora plane could look like is pictured
This has led conspiracy theorists to claim the power source could be behind a hypersonic US spy plane, dubbed Aurora.
It could be a successor to the Mach 3.35 Lockheed Martin SR-71 Blackbird craft that was retired in 1998.
These claims originated in Aviation Week & Space Technology magazine, which ran an article in 1989 about a a mysterious entry in the 1985 US budget.
It said the plane can accelerate up to Mach 6, or 4,567mph (7,349km/h) - three times faster than Concorde.
These claims originated in Aviation Week and Space Technology magazine, which ran an article in 1989 about a mysterious entry in the 1985 US budget.
The firm was said to be looking into replacing its SR-71 Blackbird, which was later retired in 1998.
However, the former head of Lockheed's Skunkworks division, Ben Rich, said Aurora was a codename for the stealth project which eventually led to the B-2 Spirit.
But, in November 2013, Lockheed Martin announced it was developing a spy plane with similar technologies called SR-72.
The firm said the plane can accelerate up to Mach 6, or 4,567mph (7,349km/h) - three times faster than Concorde.
Concorde flew no faster than Mach 2, primarily because the materials weren’t available in the Sixties that could withstand greater heat.
Technology has advanced since then, and the SR-72 will be a so-called ‘warm structure’ - it will heat up rather than reflect the heat using the sort of ceramic tiles that covered the Space Shuttle.
Concorde wasn’t allowed to fly supersonic over land because of the ‘sonic boom’ - the sound associated with the shockwaves created by a craft moving faster than the speed of sound.
Aurora is rumoured to be a top secret aircraft that has been in development since 1989. It could be a successor to the Mach 3.35 Lockheed Martin SR-71 Blackbird craft that was retired in 1998 (pictured). These claims originated in Aviation Week and Space Technology magazine in 1989
A PDE engine works by using force from a series of explosions, caused by mixing a fuel mist and air intake, to thrust itself forward. Its contrails appear to look like 'rings on a rope' (pictured), or a spine	+8
A PDE engine works by using force from a series of explosions, caused by mixing a fuel mist and air intake, to thrust itself forward. It can theoretically power planes at five times the speed of sound. A PDE can detonate between 60 and 100 times a second and its contrails appear to look like 'rings on a rope' (pictured), or a spine
According to experts, including Dr Phillip Atcliffe, senior lecturer in aeronautical engineering at Salford University, if a passenger jet flew at Mach 6 at current jet altitudes of around 30,000ft (9,144 metres), the sonic boom could damage buildings.
Officials routinely deny Aurora exists. But that has not dampened the spirits of the theorists, who point to a sighting of a mysterious triangular object by a North Sea oil engineer in August 1989.
Dr Khandelwal was keen to distance himself from the world of conspiracy theories, though he conceded there could always some things unknown to the public.
Dr Khandelwal, is among a team of scientists working on the technology behind such types of 'pulse detonation engine'.
Engine: There are a number of possible engine technologies that have been linked to the Aurora project.
In November 2013, Lockheed Martin announced it was developing for its SR-72 spy plane (pictured) said to be able to accelerate up to Mach 6	+8
In November 2013, Lockheed Martin announced it was developing for its SR-72 spy plane (pictured) said to be able to accelerate up to Mach 6
One in particular, which Dr Bhupendra Khandelwal an engineering research associate from Sheffield believes may have caused the booms heard over the UK and New York, is called a pulse detonation engine (PDE), or pulse detonation wave engine (PDWE).
At regular speeds, the craft would be powered by a traditional jet engines built into the lower fuselage.
A PDE works by sending liquid methane or liquid hydrogen into the engine. The fuel mist is then ignited.
This detonation is made inside a specially designed chamber and occurs when the aircraft is travelling beyond the speed of sound.
When the detonation occurs, the aircraft's thrust wall is pushed forward, and this is repeated numerous times to propel the aircraft forward.
Alternatively, pulsejets could compress the air caused as the craft travels forward to make it more streamline, while fuel is ignited in a combustion chamber.
Weapons: Rumours claim the Aurora may be equipped with air-to-ground weapons, but this would add weight to the craft, suggesting it is more likely that the plane would be used to reach destinations and reconnaissance missions instead.
‘When we run a test engine it’s a real industrial noise and you can hear it for miles. We have people coming to us asking to make less noise or keep it to the daytime.'
A PDE engine works by using the force from a series of explosions, caused by mixing a fuel mist and air intake, to thrust itself forward. It can theoretically power planes at five times the speed of sound.
The technology builds upon 'pulsejet' principles which first emerged in the early 1900s and were used in German V-1 flying bombs.
Test flights using the most recent forms of the technology have lasted only a few seconds, but it is still listed by conspiracy theorists as a possible way of powering the so-called Aurora spy jet.
Concorde flew no faster than Mach 2, mainly because the materials weren’t available in the Sixties that could withstand greater heat. Technology has advanced, and the SR-72 (engine details pictured) will be a so-called ‘warm structure’ - that will heat up rather than reflect the heat	+8
Concorde flew no faster than Mach 2, mainly because the materials weren’t available in the Sixties that could withstand greater heat. Technology has advanced, and the SR-72 (engine details pictured) will be a so-called ‘warm structure’ - that will heat up rather than reflect the heat
Steven Aftergood, a government secrecy expert at the Federation of American Scientists, said: 'If an aircraft is responsible, then it’s worth noting that it may not be local at all.
'Because the sound wave that causes the boom can be reflected by the stratosphere, the source of the event could conceivably be hundreds or thousands of miles away from the place where it is heard on the ground.'
But Dr Andrew Taylor, a senior lecturer in aviation at Buckinghamshire New University, said the noises did not sound like a normal sonic boom.
A supersonic plane is one that flies faster than the speed of sound, at Mach 1 or greater, using a jet engine.
Mach 2.5 is about the speed limit for gas-turbine engines. Any faster and the temperature and pressure of air entering the engine is too high for the turbo machinery inside.
To fly at hypersonic speed - Mach 5 and above - requires a different type of engine such as a supersonic-combustion ramjet, or scramjet.
These engines have no moving parts. Instead of the rotating compressor and turbine in a jet engine, air is compressed and expanded by complex systems of shockwaves under the front of the aircraft, inside the inlet and under the fuselage at the rear.
Travel becomes hypersonic when temperatures get so hot that air molecules become unstable and begin losing electrons. At these speeds the air becomes an electrically-charged field.
At supersonic speeds, air moves through a series of channels until is slowed down to a point where fuel can be more easily injected and ignited. This releases energy and thrust.
At hypersonic speed, this air moves even faster, which makes it difficult to slow down to the speed of sound and therefore requires specialist fuel and technologies, as seen in engines including the pulse detonation engine (PDE).
Air reacts like a fluid to supersonic objects. As objects travel through the air, molecules are pushed aside with great force and this forms a shock wave much like a boat creates a bow wave. The width of the so-called boom 'carpet' beneath the aircraft is around one mile (1.6km) for each 1,000ft (304 metres) of altitude	+8
Air reacts like a fluid to supersonic objects. As objects travel through the air, molecules are pushed aside with great force and this forms a shock wave much like a boat creates a bow wave. The width of the so-called boom 'carpet' beneath the aircraft is around one mile (1.6km) for each 1,000ft (304 metres) of altitude
The sonic boom is created when an aircraft or other type of vehicle flies overhead faster than the speed of sound.
Air reacts like a fluid to supersonic objects. As objects travel through the air, the air molecules are pushed aside with great force and this forms a shock wave much like a boat creates a bow wave. The bigger and heavier the aircraft, the more air it displaces.
The width of the so-called boom 'carpet' beneath the aircraft is around one mile (1.6km) for every 100ft (30.5 metres) of altitude.
An aircraft, for example, flying supersonic at 50,000ft (15,240 metres) can produce a sonic boom cone about 50 miles (80km) wide.
The maximum intensity is heard directly beneath the aircraft, and this decreases as the lateral distance from the flight path increases until it ceases to exist because the shock waves refract away from the ground.
The spread of the sonic boom depends only upon altitude, speed and the atmosphere - and is independent of the vehicle's shape, size, and weight.
Although the speed at which it was travelling, and its location above the Atlantic could reduce this altitude and spread.
Meanwhile, Professor Trevor Cox, an acoustic engineer from Salford University told MailOnline: 'To have heard a noise simultaneously in New York and the UK, the source of the sound must have been flying half way between.
'That's an awful long way - about 4,000 miles. You do get cases of sounds travelling a long way, for example, in 2005, sounds from the Buncefield fire travelled around 125 miles to Belgium.
'With smaller fighter jets just a single boom would be heard, or, as with Concorde, a "double boom" might be heard from larger aircraft as both the nose and tail cause shock waves,' he said.
'It sounds like gunfire or other ammunition, similar to what I used to hear as a child growing up in Lincolnshire when the RAF and USAF aircraft used to do bombing runs on the east coast bombing ranges.
Scramjets have been under development for decades, but a breakthrough came in May 2013, when the U.S. Air Force Research Laboratory’s Boeing X-51A WaveRider flew for 240 seconds over the Pacific on scramjet power, reaching Mach 5.1 and running until its fuel was exhausted.
Lockheed Martin's Skunk Works - builder of the Mach 3.5 SR-71 Blackbird spyplane - then unveiled plans to develop a successor, dubbed the SR-72, pictured
The next step is to build a high-speed cruise missile, able to strike distant targets in minutes, not hours.
Designed for reconnaissance and strike missions, the SR-72 would combine turbojet and ramjet/scramjet engines to enable the aircraft to take off from a runway, accelerate to a Mach 6 cruise, and then return to a conventional runway landing.
If it can secure funding from the U.S. Defense Department, Lockheed Martin believes a prototype could be flying as soon as 2023 and the SR-72 could enter service by 2030, potentially paving the way for commercial applications of scramjet technology.
Many Twitter users suspected sonic booms, similar to ones which shook Kent last month when two RAF jets intercepted a Latvian cargo plane in British airspace.
But a Ministry of Defence spokesman told MailOnline last night she had no records of any jets being scrambled.
Others suggested unusual weather conditions might be the source, but the Met Office dismissed those claims and said there was nothing out of the ordinary.
The Metropolitan Police said there had been a fireworks display in Croydon, but Twitter users insisted that could not explain sounds in Bedfordshire, Glasgow, North Devon, Leicestershire and West Sussex.
At around the same time, a loud boom was reported by a number of people in the upstate New York areas of Buffalo, Cheektowaga and Clarence more than 3,000 miles away.
But Brian Baptie, seismologist at the British Geological Survey told MailOnline: 'Micro earthquakes are small.
'Usually too small for people to feel and it’s extremely unlikely that the noises were caused by this.
'Even small earthquakes some have audible phenomenon. For example, the Folkestone earthquake of 2007, that had a magnitude of 4.3, had a loud booming noise.
'This is because the vibrations travel through the ground, and when this is coupled with the atmosphere it generates sound waves that can be heard over a large distance.
Reaction: There was an explosion of activity on Twitter, where some users came up with their own theories
Many of the reports were picked up by Twitter user Virtual Astronomer (pictured), who said space debris re-entering the earth's atmosphere could have been responsible. He also said he was convinced the noises were created by aircraft sonic booms
One possible explanation is that the loud noise and ground shaking could have been a meteorite breaking up in the atmosphere, which would result in a sonic boom - a claim backed by expert Dr Caroline Smith	+8
One possible explanation is that the loud noise and ground shaking could have been a meteorite breaking up in the atmosphere, which would result in a sonic boom - but this was dismissed by another expert
'It’s a well-known phenomenon and happens for big earthquakes, but if this was the case it would have been felt as well, too, so it is unlikely the booms would just be down to an earthquake.'
Ms Angiletta, who recorded the sounds told MailOnline: 'I was just at home watching TV when I couldn't hear the program due to the loud noises. It was very distracting as it went on for ages.
'I went out to look for fireworks but I couldn't see anything in the sky. That's when I recorded the clip to send to my family to see if they could hear the same thing.'
The 27-year-old said that her family, who live roughly seven miles away in Norbury, south London, could also hear the sounds, which lasted for about 30 minutes. She then turned to Twitter to see if anyone could explain what they were.
If an aircraft is responsible, then it’s worth noting that it may not be local at all... The source of the event could conceivably be hundreds or thousands of miles away
Many of the reports were picked up by Twitter user Virtual Astronomer, who said space debris re-entering the earth's atmosphere could have been responsible.
'Space debris such as old satellites and things can cause sonic booms heard over very large areas,' he told MailOnline. 'It's the same for big meteors or rocks that come in.
'There was very little wind last night so conditions were perfect for sound to travel very long distances.'
He told MailOnline that there was one piece of debris from Russian satellite Kosmos 2251 scheduled for re-entry, but said that the timing was 'not a good fit' for it to have been over the UK.
He added: 'I do not think it was a meteor or a piece of space-junk, as the noises mentioned spanned a large segment of time. Plus, unless it was cloudy over the U.K., there would've been visual sightings.
Dave Reed, who lives in Fareham, Hampshire, said his dogs 'went crazy for a couple of minutes' after hearing what he had assumed were fireworks.
Twitter user Carrie Proctor wrote: 'This is how we'll find our that WW3 has begun. It'll be a Twitter hashtag long before any official announcement!'
Hyacinth Fahsi, who lives in Grimbergen, near Brussels, said the sound at 11pm local time - the same time as it was heard in Britain - woke his daughter and matched the recording in Croydon.
Describing the sound as 'repetitive explosions', he said: 'I first thought it was firework but it was different. Maybe thunder, but the sky was clear and I didn't see lightning, even far away.
Do you have a recording of last night's loud bangs? If so, we would like to hear from you. Please email dan.bloom@mailonline.co.uk
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