By . Inderdeep Bains . The driver of a Porsche that careered into a broken down car killing the woman inside has been arrested, police said today. Drivers looked on in horror as the woman victim burned to death inside her blue Nissan Almera after it was catapulted 150ft along the M40 and then burst into flames. Moments earlier the powerful Porsche Cayenne 4x4 had ploughed into the tiny car that was stranded on the M40 in Buckinghamshire yesterday morning just before 10am.  Firefighters battled to free her from the inferno but she was later confirmed dead. Full details of how the smash happened are yet to emerge but police have arrested the 47-year-old male driver of the Porsche on suspicion of causing death by dangerous driving. They said the woman victim was from Birmingham and her family have been told of the accident. Burning inferno: The car burst into flames, trapping the female driver inside after a Porsche Cayenne crashed into the back of her car . Impact: The car was catapulted 50 metres along the M40 leaving a trail of debris before it burst into flames . The pensioner is believed to have been slowing to a stop moments before the collision with the Porsche travelling a short distance behind her. One onlooker said: 'The car was just a blackened wreck, and it would have been hard to survive that. 'It was a scene of devastation and it's just sad to know someone lost their life.' Another wrote on Twitter: 'Big big accident on the M40 back to London. Fatal someone got burned alive.' It took 20 firefighters to put out the blaze, with a screen being erected around the mangled car to shield motorists' view as the victim's remains were removed from the vehicle. All four lanes of the M40 southbound between junctions three and two in Beaconsfield were closed as a result of the accident. A Thames Valley Police spokesman said officers would need to use dental records to identify the badly-burned body. The Buckinghamshire Coroner's office . told the Mail Online that they are still formally identifying the . pensioner and that her name will be released once that is complete. The victim, who was travelling alone, . appeared to have broken down on the southbound carriageway near . Beaconsfield, Buckinghamshire, at about 10am. Her car slowed to a stop . in the middle lane and was struck by a Porsche Cayenne. Police said the second car's driver, a 47-year-old man, was taken to hospital for treatment to minor injuries. Shocking shell: Motorists could only watch helplessly as the victim's car was engulfed in an inferno and left totally destroyed . Screening the wreck: Fire fighters erected screens to remove the woman's charred remains while the Porsche remained with minor damage (right) What's left: The burned out shell of the victim's car was collected (top left) before the Porsche (bottom left) as rescue crews tried to clear the road quickly . 'He has since been released by medics . and has been arrested on suspicion of causing death by dangerous . driving,' a spokesman confirmed. Screens were put up in front of the . wrecked Nissan by firemen to shield the view of other drivers as they . extracted the woman's remains. All four lanes of the M40 southbound . between junctions 2 and 3 were closed as a result of the crash, causing . major delays. The route was not partially reopened until 4pm. Bumper to bumper: The four southbound lanes of the M40 were closed as a result, causing major delays for motorists heading towards London . Thames Valley Police issued an appeal for information relating to the collision yesterday. A spokesman said: 'Officers would . like to hear from anyone who witnessed this incident as well as the . driving of the car before it broke down on the motorway.' Campaigners last month called for an . overhaul of safety policies following a rise in deaths on the roads for . the first time in eight years. The number of road fatalities increased by 3 per cent to 1,901 last year – the first annual rise since 2003. The overall number of people killed or seriously injured rose for the first time since 1994 to 25,023. Road safety experts said the . Government's promise to 'end the war on motorists' should bear some of . the blame, as cuts to police, road safety budgets and speed cameras came . into effect.
The victim was a 73-year-old woman from Birmingham who had broken down on motorway .
Porsche 4x4 ploughed into flimsy blue vehicle hurling it 150ft along the busy road .
Horrified drivers looked on as pensioner was incinerated inside the wreckage .
Porsche driver, 47, arrested on suspicion on causing death by dangerous driving .
Police may have to use dental records to identify the charred body .
The four southbound lanes of the M40 were closed causing traffic delays .
By . Inderdeep Bains . The driver of a Porsche that careered into a broken down car killing the woman inside has been arrested, police said today. Drivers looked on in horror as the woman victim burned to death inside her blue Nissan Almera after it was catapulted 150ft along the M40 and then burst into flames. Moments earlier the powerful Porsche Cayenne 4x4 had ploughed into the tiny car that was stranded on the M40 in Buckinghamshire yesterday morning just before 10am.  Firefighters battled to free her from the inferno but she was later confirmed dead. Full details of how the smash happened are yet to emerge but police have arrested the 47-year-old male driver of the Porsche on suspicion of causing death by dangerous driving. They said the woman victim was from Birmingham and her family have been told of the accident. Burning inferno: The car burst into flames, trapping the female driver inside after a Porsche Cayenne crashed into the back of her car . Impact: The car was catapulted 50 metres along the M40 leaving a trail of debris before it burst into flames . The pensioner is believed to have been slowing to a stop moments before the collision with the Porsche travelling a short distance behind her. One onlooker said: 'The car was just a blackened wreck, and it would have been hard to survive that. 'It was a scene of devastation and it's just sad to know someone lost their life.' Another wrote on Twitter: 'Big big accident on the M40 back to London. Fatal someone got burned alive.' It took 20 firefighters to put out the blaze, with a screen being erected around the mangled car to shield motorists' view as the victim's remains were removed from the vehicle. All four lanes of the M40 southbound between junctions three and two in Beaconsfield were closed as a result of the accident. A Thames Valley Police spokesman said officers would need to use dental records to identify the badly-burned body. The Buckinghamshire Coroner's office . told the Mail Online that they are still formally identifying the . pensioner and that her name will be released once that is complete. The victim, who was travelling alone, . appeared to have broken down on the southbound carriageway near . Beaconsfield, Buckinghamshire, at about 10am. Her car slowed to a stop . in the middle lane and was struck by a Porsche Cayenne. Police said the second car's driver, a 47-year-old man, was taken to hospital for treatment to minor injuries. Shocking shell: Motorists could only watch helplessly as the victim's car was engulfed in an inferno and left totally destroyed . Screening the wreck: Fire fighters erected screens to remove the woman's charred remains while the Porsche remained with minor damage (right) What's left: The burned out shell of the victim's car was collected (top left) before the Porsche (bottom left) as rescue crews tried to clear the road quickly . 'He has since been released by medics . and has been arrested on suspicion of causing death by dangerous . driving,' a spokesman confirmed. Screens were put up in front of the . wrecked Nissan by firemen to shield the view of other drivers as they . extracted the woman's remains. All four lanes of the M40 southbound . between junctions 2 and 3 were closed as a result of the crash, causing . major delays. The route was not partially reopened until 4pm. Bumper to bumper: The four southbound lanes of the M40 were closed as a result, causing major delays for motorists heading towards London . Thames Valley Police issued an appeal for information relating to the collision yesterday. A spokesman said: 'Officers would . like to hear from anyone who witnessed this incident as well as the . driving of the car before it broke down on the motorway.' Campaigners last month called for an . overhaul of safety policies following a rise in deaths on the roads for . the first time in eight years. The number of road fatalities increased by 3 per cent to 1,901 last year – the first annual rise since 2003. The overall number of people killed or seriously injured rose for the first time since 1994 to 25,023. Road safety experts said the . Government's promise to 'end the war on motorists' should bear some of . the blame, as cuts to police, road safety budgets and speed cameras came . into effect.
Almera after it was catapulted 150ft along the the powerful Porsche Cayenne 4x4 had ploughed male driver of the Porsche on suspicion of causing death by dangerous driving. They said the woman victim was from Birmingham and her family to use dental records to identify the badly-burned body. The Buckinghamshire Coroner's have broken down on the southbound carriageway southbound lanes of the M40 were closed as a