It is not normal to have a full blown inquiry after every accident

Department of Environment, Transport and the Regions

But Health and Safety Executive (HSE) officials say the criminal prosecutions are being seriously considered.

If the case does reach court, it would be alleged that executives had failed to take action to replace the defective rail thought to have caused the accident.

Four people died and more than 30 were injured in the crash at Hatfield on 17 October

A preliminary Health and Safety Executive report found that a broken rail was the "substantial" if not the only cause of the crash.

Police investigation

Railtrack has admitted that mistakes were made.

Faulty track was scheduled for replacement but the work was not carried out.

British Transport Police investigating the accident have interviewed a number of employees at Railtrack and Balfour Beatty to determine the exact maintenance schedule of the track where the derailment happened.

Further interviews will be held over the next few weeks before officers submit a report to the Crown Prosecution Service.

Lawyers will then decide whether charges should be made and a decision is expected within weeks.

Police have been waiting for technical evidence about the cause of the accident before completing their inquiries.

'No public inquiry'

The HSE is due to present its second interim report on the causes of the accident on Tuesday.

Meanwhile, experts in Sheffield are conducting tests on 300 pieces of broken track.

But ministers have ruled out a public inquiry.

A Department of Environment, Transport and the Regions (DETR) spokesman said the case for a public inquiry "had not been made".

But the DETR is refusing to comment on suggestions that a lengthy public inquiry, possibly lasting more than two years, had been avoided as it could delay possible criminal proceedings.

"It is not normal to have a full blown inquiry after every accident," the spokesman added.