Six people were today feared dead after an East Anglian-bound train came off the track at Potters Bar to the north of London.The West Anglia Great Northern service was travelling from Kings Cross to Kings Lynn via Cambridge and Ely.

SIX people were today feared dead after an East Anglian-bound train came off the track at Potters Bar to the north of London.

The West Anglia Great Northern service was travelling from Kings Cross to Kings Lynn via Cambridge and Ely.

The four-car electric train is reported to have come off the track, hit a bridge and exploded.

Six people are reported to have died and 15 were seriously injured in the accident.

Initial reports said three people had died, but this figure rose as medical staff started work.

One of the carriages is reported to have hit a platform at Potters Bar station shortly before 1pm today.

There were reports that a metalic object had been seen on the track near where the train derailed shortly before the tragedy.

The derailment was close to Hatfield where a GNER express came off the tracks in October 2000 in an accident which claimed four lives.

British Transport Police said officers were on their way to the scene, confirming that there had been a derailment near Potters Bar.

The rail line at Potters Bar is shared by high-speed express trains from London to Edinburgh and local services from Kings Cross to Peterborough, Cambridge, and Kings Lynn.

The line is fully electrified

Hertfordshire said they expected to find "a significant number" of casualties in the aftermath of the accident.

Witness Nicholas Anastasiou said he heard a "big bang and that was it.'

He said: "One carriage is very badly damaged indeed. In the car park there are bits of the train everywhere.

"People are quite badly hurt. There are loads of hurt people here.

"There are people running around trying to help people but I don't think they can do much because it's quite bad. All I can see is the last carriage.'

Police confirmed there were "walking wounded' from the derailment but could not confirm reports of deaths or serious injuries.

An ambulance service spokesman said early reports suggested a "significant number of casualties" but said initial assessments were still being carried out.

Eyewitnesses said the final carriage had hit the railway station platform, with reports that part of the train had hit a bridge.

Railtrack confirmed the train had four carriages, three of which had derailed.

Hertfordshire police have issued a telephone number for anybody concerned about friends or relatives who may have been travelling on the train.

The number is 01707 354158.