Two people were hospitalised after a fire broke out on a London train during rush-hour earlier this morning.
The blaze which caused smoke to billow out from a Bakerloo line train as passengers stood in the dark in fear started because of an electrical fault.
Passengers fled Oxford Circus station in pain as the train arrived into the station, and filled the underground in smoke.
Oxford Circus station, which services London's busiest shopping street and sees thousands of commuters pass through it during the rush-hour, was closed after the incident.
Transport for London confirmed the fire was caused by an electrical fault and said a 'comprehensive investigation' will take place.
Nigel Holness, London Underground's director of network operations, said: 'The cause of the smoke was an electrical fault under one of the carriages, which resulted in a small fire that was quickly extinguished. Understandably this was a distressing incident for our customers, for which I give my sincere apologies.
'A comprehensive investigation into how this incident could have occurred is now under way.
'Our Sarah Hope Line, which is set up to help those affected by incidents on the transport network, is also available to offer support.'
A London Ambulance Service spokesman said medics were called at 8.53am on Friday to reports of an incident on board a Bakerloo line train at Oxford Circus Tube station.
He added: 'We treated four patients at the scene for smoke inhalation and have taken two to hospital as a precaution.'
Shocking photographs taken by passengers showed trapped commuters holding their nose on board the train and clouds of smoke pouring from the carriage at it arrived into the station.
Reports on social media describe how alarmed commuters and tourists were seen running up the stairs, away from the platform as smoke filled the underground tunnel.
One woman said the evacuation process was '******* terrifying' as they had no idea what was going on.
The station was closed while the Bakerloo Line was suspended as emergency services investigate.
Those caught up in the panic have taken to social media to describe the incident.
Commuter Katie Watts posted to Twitter: 'Just got off the tube at Oxford Circus and the train across the platform was on fire, got evacuated out.'
She said the evacuation was orderly but another disagreed, describing it as 'absolute madness'.
Tom Richell was about to enter the station as alarms were sounded. He told The Sun: 'People were flooding out of the station. An alarm was going off with an announcement asking for the 'captain'.
'One woman looked at me and said 'don't go down there. Just get back'. She looked scared.
'Police arrived around three mins later. One small van at first then around three others then two fire engines.'
A video taken by a passenger appears to show the Tube train in a tunnel and an alarm can be heard beeping.
Joe Bunting tweeted: 'Fire on the bakerloo line Oxford circus today - great Friday start.'
While @lucyjanefunnell posted: 'There's a fire at Oxford Circus tube. Bakerloo line is on fire and you can smell the black smoke going through. Hope everyone is ok!'
Source: Daily Mail.