King's Cross station has been evacuated by a fire alarm sounding in the Underground section of the station.
Passengers were cleared from the station at around 4pm, raising the possibility of rush-hour delays to journeys.
A (BTP) spokesman said the source of the alarm was area of King's Cross which contains the Tube lines.
London Underground lines which run through King's Cross are the Northern Line, Circle Line, Metropolitan Line and Hammersmith and City line.
British Transport Police (BTP) attended the scene to help with the evacuation, which was due to a false alarm.
A Transport for London spokesman confirmed there was no fire emergency at the station.