Hundreds of rail passengers were trapped in overheated carriages for hours yesterday after a power failure left trains stranded outside stations.

Police, fire crews and paramedics were drafted in to treat passengers after six trains were left stranded between Huntingdon and Peterborough stations on the East Coast Mainline.

Up to 300 passengers were trapped for two hours in the 2.55pm train from Newcastle to London King's Cross, which came to a halt in Sawtry.

Dozens fainted in the heat, with temperatures rising as high as 115F.

Passenger Michael Steed, 70, said: "It was dreadful. People were fainting and repeatedly pulling the emergency cord.

"Eventually a woman having a panic attack grabbed an emergency hammer and broke through a window and they eventually opened the doors."

The passengers had to help each other down a 6ft drop to get off the train.

Firefighters and paramedics arrived to administer first aid and the Cambridgeshire Police helicopter flew in water and medical aid.

Another passenger, Simon Walker, said passengers "rebelled" after conditions got unbearable in the train.

"There are some people suffering quite badly," he said.

"They ran out of water and in the end they were giving away everything free. I've seen people walking around with bottles of champagne just to get some liquid into them."

More than 700 passengers, including MP for Grimsby Austin Mitchell, were evacuated from the six trains throughout the evening, with a four further trains stranded in stations.

Mr Mitchell said he believed the air conditioning failed in the train, which added to the problem.

Kevin Groves, spokesman for Network Rail, said: "We have engineers working to fix the problem and they will work throughout the night in a bid to have trains running again by 6am."

John Gelson, spokesman for GNER, said: "Passengers on the 2.55pm Newcastle to King's Cross train evacuated to the trackside where assistance for those who need it was given.

"We fully appreciate how unpleasant an experience this has been for passengers and apologise to them.

"A full and detailed investigation into what happened is under way."