Hundreds of rush-hour Tube train passengers were led to safety by fire crews and London Underground staff after smoke billowed from beneath a crowded carriage.

A passenger raised the alarm as the Northern Line train pulled into a Tube platform at Euston station, said an Underground spokesman.

The smoke was coming from an under-floor air compressor, he said. All passengers from the train had to leave the station as the smoke spread, and the line was closed.

A following train was trapped in the tunnel, and passengers from it were led along the track for "a short distance" to reach the platform at Euston.

Smoke inhalation

A London Fire Brigade spokeswoman said the fire was small and crews put it out using extinguishers.

London Ambulance Service told the BBC it had taken one person to hospital, believed to be suffering from smoke inhalation, but no-one was seriously hurt in the incident which saw about 300 passengers led to safety.

Euston Underground station was still closed nearly two hours after the incident, with trains diverted or running through without stopping, while work continued on rectifying the train fault.

An Underground spokesman said it was not clear how long the station would remain closed.