Relatives of those who died in some of Britain's worst train crashes have criticised the Government over its plans to scrap the independent regulator in charge of rail safety.

Alistair Darling, the Secretary of State for Transport, is considering ending the involvement of the Health and Safety Executive, which was put in charge of rail safety after the Clapham disaster in 1988, which killed 35.

The uncertainty over the future of rail safety coincides with a long battle behind the scenes in Whitehall over a promise made in Labour's last election manifesto to introduce a new offence of corporate manslaughter, to make it easier to prosecute in cases where bad management has led to a fatal accident.

Mr Darling is known to be unhappy about the huge costs of policing rail safety, including the vast programme established after a faulty piece of track led to four deaths in the Hatfield train crash in October 2000.

Next month, Mr Darling will publish a major document on the future of the railway system. However, he will risk a political storm if he attempts to bring control of rail safety back into the Transport Department.

Lord Cullen, who headed the official inquiry into the Clapham disaster, warned that it was "essential" that the safety regulator was "clearly seen to be independent".

Maureen Kavanagh, from the Safety on Trains Group, whose son Peter died in the 1997 Southall rail crash, said: "It seems rather extraordinary, when public confidence in the safety of the railways is so low, for the Government to consider removing the independence of the safety regulator."