Holborn Station was evacuated this morning after smoke engulfed a Central Line train during rush hour.
The authorities were called to the scene after receiving reports of a 'loud bang' and smoke around 9:20am on Tuesday.
Posts on Twitter show the train halted at the platform with a thick haze in the air, while a tannoy makes an emergency announcement.
The London Fire Bridge has said the bang was caused by an overheated compressor on a train, not a fire.
Transport for London has said the station is now fully open once again, and trains are stopping as normally.
The incident adds to travel disruption across the capital on Tuesday, after a train derailed around Waterloo Station and another crashed into buffers at King's Cross.