With her head bowed in sombre reflection, she was briefed on the latest efforts to identify victims which are continuing at the disaster scene.

She had earlier flown especially from Balmoral in Scotland to the scene of the west London rail crash which has claimed at least 30 lives.

From a specially constructed platform the Queen looked over the remains of some of the most badly damaged carriages.

The BBC's Ben Brown:"The search for clues goes on"

The Queen, accompanied by British Transport Police Chief Constable David Williams, his Assistant Chief Constable Paul Nicholas and Metropolitan Police Deputy Assistant Commissioner Andrew Trotter, praised the efforts ot the emergency crews.

Witnesses said that the Queen looked concerned as she was told of how the crash happened and how a signalman who realised what was taking place had been unable to act.

The Queen was then led past the hundreds of bouquets of flowers left as a tribute to the dead.

There are fewer fatalities than originally feared

After the Queen's visit, Mr Williams said she had expressed a great interest and knowledge of what has happened.

He said: "She said she had seen a number of the pictures on television and heard briefings and very much wanted to come and see for herself.

"She was very concerned and wished to share that concern with the people in involved."

BBC's Peter Gould: "The Queen spent about 15 minutes at the crash site"

Mr Trotter said the Queen was moved by what she saw.

"To see it at first hand, to see the wreckage and the pure scale of the crash was obviously something that she felt had made quite an impact.

"She said it was awful and made the point very strongly that it was ordinary people going about their ordinary business and how shocking that was."

Inferno carriage to be moved

Crash scene workers are preparing to lift the charred remains of the worst damaged carriage in the disaster from its shrouds of tarpaulin.

Carriage H still shrouded in tarpaulin

Forensic experts have spent more than two days sifting through ash and debris inside Carriage H in which many people were initially feared to have perished.

Assistant Deputy Commissioner Andy Trotter said that although the remains of just one body were discovered yesterday, there was a possibility that other passengers might be found underneath the devastated carriage.

He said the carriage would be lifted and airbags placed underneath so a thorough search could be conducted.

Once this had been completed the carriage would be put on a low loader and taken away from the scene for more tests, he added.

The task of identifying victms has been made easier by the discovery that the initial estimates of the temperature of the fire in carriage H had been too high. But the fire is now thought to have still reached 600 degrees centigrade.

Call for combined inquiry

Meanwhile, lawyers acting for the families of victims of the Southall rail disaster have told its public inquiry that it should be merged with the coming investigation into the Paddington rail crash.

The BBC's Stephen Evans reports: "There is pressure on the government"

Announcing they were writing to the Deputy Prime Minister John Prescott, the lawyers said that a single super-inquiry into two of the worst rail disasters in British history would provide the investigation with the power it needs to force through major changes in safety.

Inquiry chairman Professor John Uff QC said time was needed to see how "overlapping" issues surrounding the two tragedies should be explored.

The inquiry also heard from Anthony Scrivener QC, representing rail union Aslef, who called for control of the railway infrastructure to be brought back into public ownership.