Mr Boateng said too much time had elapsed to call a public inquiry into the death, which took place during a protest against a rally held by the far-right-wing National Front (NF).

A Home Office spokeswoman said that while there was "understandable disquiet" at the time because of the then government's failure to set up an inquiry, it was now so long ago it was "doubtful" whether one would shed any light on the case.

But Mr Boateng did pledge to commemorate the "tragic" death of Mr Peach, who was 33 when he died.

'Lessons learned'

Mr Boateng met Celia Stubbs, 58, who was Mr Peach's girlfriend for eight years. She wrote to Home Secretary Jack Straw requesting that the case be reinvestigated by the new Racial Crimes Task Force.

Mr Boateng spoke of what could be gained out of the "tragedy" of Mr Peach's death.

"Lessons have been learned from the circumstances of his death about the policing of public order incidents and the importance of good police-community relations," he said.

"It is right that we should commemorate the 20th anniversary of his death.

Aim for 'fair, equal society'

" I look forward to doing so in a way that recognises how far we have come since then, and what we have yet to do to achieve the just, fair and equal society for which he worked and died."

Mr Peach, a schoolteacher, died from a blow to the head as police tried to disperse a crowd of thousands of people.

The Socialist Workers' Party member was protesting against the National Front rally, which was held on April 23 1979, St George's Day. It was part of the NF's general election campaign in Southall, west London, an area with a high population of ethnic minorities.

Eleven witnesses claimed to have seen members of the Metropolitan Police Special Patrol Group (SPG) hitting Mr Peach in a side-street at the height of the violence. No officers were charged with the alleged attack.

Request for racial probe

An inquest recorded a verdict of death by misadventure, and the Met reached an out-of-court settlement with Mr Peach's brother in 1989.

Jack Straw was a backbencher when he and 79 MPs called for a public inquiry into the case after the inquest, but the request was rejected by the government.

A Home Office spokeswoman said Mr Boateng had not yet decided how the commemoration would take place.