Reports of smoke billowing from a tunnel caused chaos on the rails - even though there was no fire, it was revealed today.

About 70 firefighters - 35 each from Kent and Essex - rushed to the Thames Tunnel on the line between Ebbsfleet and St Pancras last night.

Train services were halted as hundreds of frustrated passengers were left stuck on stationary trains.

All services between 6pm and 8pm were affected, including 10 high speed trains.

But when fire crews arrived there was no blaze. Firefighters walked the entire length of the 2.5km tunnel, carrying out tests using thermal imaging, but nothing out out the ordinary was found. They eventually left at about 10pm.

The alarm was raised following reports of smoke coming from a fan room in the tunnel.

A spokesman from Kent Fire and Rescue Service said it is their policy to mobilise a large number of firefighters to such incidents, as a precaution.

Southeastern Trains confirmed this morning that all services have been resumed.

Commuter Rose Barman, 37, was trying to get home to Ashford on the 5.40pm service from St Pancras when the HS1 service came to an abrupt halt.

The interpreter, who should have arrived at Ashford by 6.15pm, instead found herself boarding a replacement bus service at Stratford just before 8pm having spent over an hour on the stranded service.

Mrs Barman said: "The information was a bit vague as to what or where the incident was, but we were given regular updates."