A tube carriage caught fire at Oxford Circus, causing a mass evacuation which witnesses described as terrifying.

There were casualties after the fire, with four patients treated by the London Ambulance Service and two taken to hospital.

The station was fully operational by 11am after the scene was attended by the London Fire Brigate.

The Bakerloo Line was suspended after smoke was seen billowing out of one of its trains and witnesses reported the smell of burned plastic.

Commuters were pictured shielding their faces from thick smoke which billowed through their carriage.

Commuters were told at rush hour to take other routes as one of London’s busiest tube stations was evacuated.

A witness said the smoke was spreading, tweeting: There has been some of fire at Oxford Circus. Smoke in the tunnels and station evacuated. Avoid area!

Very scary moment on the Bakerloo: emergency alert at Oxford Circus and then as we went through the tunnel the carriage filled with smoke.

The London Fire Brigade said: Crews have been called to #OxfordCircus tube station and are currently investigating reports of smoke, and the British Transport Police tweeted: We’re currently at #OxfordCircus after reports a fire alert on a Bakerloo Line train. Station is currently shut.

The British Transport Police added that the fire is not currently being treated as suspicious.

Nigel Holness, London Underground’s Director of Network Operations said: At around 8:50am our staff were alerted to reports of smoke on a Bakerloo train approaching Oxford Circus. Our staff immediately contacted the emergency services, who quickly attended, and ensured customers left the train and exited the station.

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 underway. Our Sarah Hope Line, which is set up to help those affected by incidents on the transport network, is also available to offer support.