Contractor Balfour Beatty has admitted it breached safety standards before the Hatfield train disaster that killed four people in October 2000.

The firm’s change of plea came after it was formally cleared by an Old Bailey judge last week of a corporate manslaughter charge.

Five rail bosses were cleared of unlawfully killing four people in the 115 mph crash on 17 October 2000. They still face charges under the Health and Safety Act and their trial will continue.

As the defence case began, Ronald Thwaites, Balfour Beatty’s counsel, said the company wished to plead guilty to the Health and Safety Act charge. He read out the basis of its plea of guilty, which did not accept all the allegations outlined at the start of the case. Balfour Beatty claims the crash had a number of causes.

Richard Lissack, prosecuting, told the court: "We continue to maintain that in the totality of the indictment this company is guilty."

The five rail executives who face Health and Safety Act charges are Anthony Walker, Balfour Beatty Rail Maintenance’s regional director, Nicholas Jeffries, its civil engineer, Alistair Cook and Sean Fugill, managers of Railtrack London North East zone, and Keith Lea, Railtrack LNE track engineer. All deny the charge.

Balfour Beatty does not accept it had failed to comply with Railtrack’s mandated standards.