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Police have confirmed 27 people are dead but many more bodies are believed to be inside a first-class carriage gutted by fire when two trains collided just outside Paddington Station.

The accident, at 8.11am on Tuesday, involved a Great Western express which had left Cheltenham, Gloucestershire, two hours before, and a Thames Trains service heading for Great Bedwyn in Wiltshire.

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British Transport Police has set up four crash information centres for relatives of the missing passengers. They are at the Thistle Hotel in Swindon, the Thistle Hotel in Cheltenham, Reading railway station and the Royal Lancaster Hotel in Bayswater, central London.

Relatives' fears

Experienced trauma counsellors have been called in to help the relatives.

About 20 friends and relatives were in tears as they arrived at the Royal Lancaster Hotel.

Detective Superintendent Shaun Sawyer, who is handling the family liaison for the crash, said:"This is an initial meeting with families who genuinely fear that their loved one may have died in this accident."

He said: "Some people have come on their own and some people have come with friends and relatives.

"What they are going through at the moment I cannot comprehend."

'Identification difficult'

Mr Sawyer said those living outside London would be asked if they wanted to travel to the capital or stay at home and keep in touch by telephone.

He said identification could prove a difficult and lengthy process - as it was after the 1988 King's Cross fire - and he added: "The coroner has made clear that he will not confirm identification until he is absolutely sure."

Dental records, jewellery, tattoos, clothing and documentation would be used to help identify the victims.

Counsellors will also be on call to help with crash victims and rail staff who are suffering emotionally in the aftermath of the crash, one of the worst in the history of British railways.

A spokesman for First Great Western, Austin Milne, said the severity of the fire which the crash triggered meant it could take several days to identify the bodies on board.

He said: "The coroner, police and rescue agencies are endeavouring to ensure that the earliest possible contact is made with relatives and partners and that identification of the deceased takes place.

"It is most likely that this process will take many days because of the scale and intensity of the accident."

Unclaimed cars

Both drivers are believed to have been killed in the crash, which occurred at Ladbroke Grove, just west of Paddington.

An eerie reminder of the crash was the sight of almost 100 unclaimed cars at Reading railway station car park.

Some of the drivers are believed to have been killed, others are lying injured in hospital.

Survivors of Tuesday's crash were back at Kemble station on Wednesday for the dawn train

Many of the dead are expected to come from towns and villages in the West Country.

The express train called at Cheltenham, Gloucester, Stroud, Kemble, Swindon, Reading and Maidenhead on its way into Paddington.

The slower train was heading for the small Wiltshire village of Great Bedwyn, home to many long-distance commuters to London.

The village vicar, the Reverend Rodney Harrison, said the community would be saying prayers for people involved in the crash.