London commuters faced traffic chaos this morning while thousands are still without power as firefighters battle to extinguish an underground blaze that has been raging for more than 24 hours. More than 2,000 office workers had to be evacuated yesterday due to the fire in Holborn which apparently started in a tunnel carrying electrical cables, causing flames to erupt from the pavement and filling the area with smoke. Although the blaze has now been brought under control it has not been put out entirely, and firefighters still do not know the cause of the fire. Scroll down for video . Blaze: The scene in Holborn today, where a fire has been raging for more than 24 hours . Emergency: Firefighters and gas workers were still battling to put out the fire a day later . Plume: Flames rose up from the street in the deserted part of central London today . Continuing: Firefighters spraying water into a manhole in a bid to put out a fire in Holborn . Much of the area is cordoned off as firefighters struggle to extinguish the fire, while there were reports of major delays in central London. Commuters were urged to avoid travelling through Holborn if possible, and firefighters were unable to estimate when the situation might return to normal. Tonight 35 firefighters and police officers remain at Kingsway, where flames were seen erupting from a manhole cover yesterday. Kingsway is closed, as is the Strand underpass, while Waterloo Bridge is closed northbound. Transport for London said that 15 bus routes were being diverted, and witnesses described seeing dozens of buses backed up along High Holborn, but Underground services have returned to normal. More than 1,000 buildings remain without power today, with businesses, government departments and tourist attractions forced to close ahead of the Easter weekend. firefighters and gas workers continue to tackle the flames in the Kingsway Service Tunnel . Carnage: Parts of the road had to be dug up in an attempt to extinguish the fire below the ground . The underground fire has stopped power workers from accessing their equipment . Jets: Firefighters deployed multiple hoses to combat the blaze which wreaked havoc on the area . Exhausted: Firefighters looked tired as they took a break after working at the scene for hours . Blocked: Roads were closed in the wake of the fire, whose cause is still unknown . UK Power Networks said that 100 staff had worked through the night to restore electricity to the area, but it is not known when buildings will regain power. A spokesman said: 'A major gas fire in an underground tunnel is still burning so we cannot yet access our equipment. 'Our engineers have restored power to 2,000 customers and the remaining 1,100 will regain power through generators and cable works as soon as possible. 'We had over a hundred staff working through the night and work continues today. 'We are working with the emergency services and other agencies to keep affected customers updated. The cause of the incident is being investigated.' Fire crews last night doused the hole with water before they smashed the cover open with a sledgehammer, and continued to pump in water from multiple hoses. Peter Cowup of London Fire Brigade said that the fact the fire started in an underground tunnel meant it had been tricky to bring it under control. 'This has been a technically difficult incident to tackle,' he said. 'The reason that the fire is still burning is because the service tunnel is hard to reach and although firefighters have been applying water through access points throughout the night, the complexity of the tunnel layout means that it will be some time until the fire is fully extinguished. 'However, the fire is contained and we are making steady progress and working with the utility companies and the police to bring this incident to a close.' Works: More than 100 power workers were deployed to restore electricity to businesses in central London . Disruption: The road closures were said to have caused severe traffic jams in the surrounding area . Peter Cowup of London Fire Brigade said the blaze was 'a technically difficult incident to tackle' Deserted: The Holborn area was emptied of workers and shoppers thanks to the disruption . Closure: Shops had signs in their windows apologising for the inconvenience . One council boss warned that there was a 'worrying trend' of pavements exploding in central London and said that businesses had been hit by the accidents. 'We do not fully yet know what caused the fire in Holborn on Wednesday,' said Richard Beddoe of Westminster Council. 'However, pavements have exploded in central London previously and it is a very worrying trend. 'Our message remains the same - we want to see better investment in the capital's infrastructure, as it benefits the whole UK. 'We are relieved to hear that there were no serious casualties, but the losses to big businesses in the West End, due to poor infrastructure, is just not acceptable. We want to see action.' In July, Piccadilly Circus was closed after an electrical fault beneath a manhole cover caused an explosion which resulted in a lorry catching fire. Meanwhile, in February last year, 50 people were evacuated from a street in north London after a pavement burst into flames. And in April 2013, a fireball burst from a pavement in Pimlico Road, central London, narrowly missing a passer-by standing yards away. A UK Power Networks spokesman said: 'There have been a small number of incidents disturbing pavements over recent years, caused by a variety of reasons and affecting utility infrastructures underground.' Blackout: Power was knocked out across the area and more than 1,000 buildings remain without electricity . Dramatic: This aerial image shows how a wide area of London was left without power . Scene: These file photos show tunnels under Holborn near to where the fire broke out . Smoke: More than 2,000 workers were forced to flee their central London workplaces . Among the buildings affected by the fire is the Royal Courts of Justice, home to the High Court and Court of Appeal, which was due to remain closed all day. Somerset House, the London School of Economics and the London Transport Museum were closed, while the English National Ballet cancelled its planned matinée performances of Swan Lake. One of the offices affected by the fire was that of HM Inspectorate of Prisons, which is closed as a result of the power cut. Gillian Perham, 54, lives near the fire and said there had been similar incidents in recent years. 'There was an exploding pavement not far from here last year,' she said. 'We are fed up with it. I'm terrified it's going to happen when I'm near one.' At one point yesterday, 70 firefighters and 10 engines were at the scene of the blaze, which forced a number of West End theatres to cancel shows last night, including The Lion King, Charlie and the Chocolate Factory and The Play That Goes Wrong. In a separate incident, 15 engines were called to a fire on an industrial unit in north London.
Main roads in Holborn are closed more than 24 hours after fire broke out . More than 1,000 buildings remain without power as a result of the blaze . Local businesses, government offices and tourist attractions are closed . Commuters have been warned to avoid the area as witnesses describe long queues of buses .