British Transport Police (BTP) have confirmed they still don't know the identity of five people seen working on the railway line just four hours before the Potters Bar rail disaster.

The admission was made by BTP's Chief Superintendent David Hatcher who told the BBC a CCTV tape of the five men seen working at the set of points responsible for the crash had been sent to the FBI for enhancement.

The news comes after the BTP set up a special hotline so that rail workers with information can contact them in confidence. Officers believe rail workers may be reluctant to give evidence to police owing to peer pressure and see the hotline as a way of encouraging staff to come forward.

Detective Superintendent Paul Crowther, who is leading Operation Declare, said: "We feel there are people in the rail industry with knowledge of the work and working practices in the Potters Bar area who still have useful information to give us.

"We are not saying people are deliberately hiding anything but peer pressure, anxiety and a reluctance to be seen talking to the police can be significant factors in impeding the free flow of information."

Rail workers who may have information which may help the BTP in their inquiry are asked to call the hotline in confidence on 020 7887 6864.

* Colin Skellett, the businessman being investigated by police on suspicion of receiving a bribe connected with the take-over of Wessex Water, has stepped down as chairman of Jarvis.

Mr Skellett is also chairman and chief executive of Wessex Water and last Thursday he was arrested by City of London fraud squad officers on suspicion of receiving a bribe of nearly £1m, related to the sale of that company to Malaysia-based YTL Power.