Passengers caught up in the horrific rush hour rail crash near London's Paddington Station told of desperate screams for help as fire surged through carriages.

One said the London-bound train seemed to have gone "right through the middle" of the Thames train heading to Wiltshire.

Passengers spoke of screaming and crying as fire engulfed carriages, while another described the aftermath as "carnage".

And others described seeing other passengers covered in blood while one carriage was said to have been "crushed to a pulp of metal".

Ian Lees, a passenger on the First Great Western train going into London, said the train appeared to have gone "right through the middle" of the Thames train heading to Wiltshire.

"We were going quite fast and there was this almighty crash and it felt like we came off the rails and it seemed to go on for ever and ever.

"It seemed like we went right through the middle of the Thames train. We must have split the diesel tanks because the fire started immediately. There were a lot of people burnt. The people who suffered the worst were the Thames passengers. We went right through the middle of them at speed."

Passenger Chris Goodall said: "The train slowed very rapidly but didn't stop, the lights went out and the fire started almost immediately and the carriage was full of smoke.

"There was screaming and crying. It was hot and smoky and there was a guy trapped underneath a seat."

Mr Goodall said he and other passengers tried to help the driver of the train, who was semi-conscious and trapped in his cab.

Another passenger, Mark Rogers, said: "I can't describe the scene - it is pretty horrible."

'Huge explosion'

Mark Palmer, who was walking nearby when the accident happened, said there was a scene of "carnage".

Passengers told of some of the injured being trapped

He said: "It is horrendous. There was a huge explosion which lasted for about 15 seconds and then there was billowing smoke. I thought a local supermarket had been blown up.

"They have been pulling people out of the carriages and using cutting equipment to get them out."

BBC Radio 5 Live reporter Phil Longman, who was also on board one of the trains, said: "There was an initial bang and the train seemed to leap in the air and I thought 'Oh Christ this is it'.

"There was another bang and I was flung forward and I saw a piece of wreckage to the side of the window ... I thought the wreckage was going to come through the window.

"The guard came on the tannoy and told people to walk to the back of the train.

"You could hear him calling out for help from the emergency services. He said 'major emergency, major emergency'."

Another passenger said "It was absolutely horrific - we could hear screams from one woman pleading to get her out. I don't know if she survived - it would be a miracle if she did."

'Flaming debris'

IT consultant David Taylor, 34, described the scene as chaos.

He said: ''I knew we had hit something very hard but all I could think about was if I would get back home to see my wife and my five-week old baby.''

Alan Macro, who was on the Great Western service going into Paddington, said: "Outside there was flaming debris going past and there was smoke everywhere. It was very frightening but we managed to get off."

A passenger on the train travelling out of Paddington told how he had survived a minor plane crash just two weeks ago.

Patrick Welcome heard a screech of brakes and was then showered with glass.

'Pulp of metal'

He said: "People in the carriage were just dripping with blood. There was a big hole torn out of the train and someone tried to put a ladder up so that people could get out.''

Mr Welcome said just two weeks ago a plane he was travelling on overshot the runway in Bangkok and collided with trees.

Stuart Allen, 28, said fellow passengers smashed windows in desperation fearing the train would explode.

"I could see flames shooting up outside the train and everyone was petrified the whole thing would go up in a ball of fire," he said.

Mr Allen, from Reading said one of the carriages on the train travelling out of Paddington was completely crushed: "There was nothing left of it, it was just a pulp of metal."