The fight against institutional racism in British policing has “stagnated” in the two decades since a landmark report into Stephen Lawrence’s death, MPs have been told.

The murdered black teenager’s mother, Baroness Lawrence, told the Home Affairs Committee she had seen little progress on 70 recommendations made in the 1999 Macpherson report.

“It just seems as if things have become really stagnant and nothing seems to have moved,” she said.

“I think people are trying to hide behind saying, ‘We don’t have any problems so there’s nothing to report’.”

But citing high rates of exclusion of young black boys in school, lower educational attainment and rising knife crime, Baroness Lawrence said: “If the amount of white kids were being murdered on our streets as the amount of black kids, society would not have sat back and allowed that to happen.”

The Home Affairs Committee is running an inquiry to mark the 20th anniversary of the Macpherson report into Stephen’s murder, investigating what progress has been made to overcome institutional racism.

The investigation comes amid a separate public inquiry into undercover policing, which will include a probe into spying on the Lawrence family but has been beset by delays and controversy.

Baroness Lawrence accused authorities of obstructing the “true facts of what happened” and claimed that chairman Sir John Mitting has not appreciated the lengths an officer would go to in order to keep their activity secret.

“This has been going on for three years now and he still hasn’t taken evidence,” she added. “They’re still going through the paperwork.

The life and legacy of Stephen Lawrence Show all 7 1 /7 The life and legacy of Stephen Lawrence The life and legacy of Stephen Lawrence SU-50-Lawrence-1-REUT.jpg Neville Lawrence addressing the media last week Reuters The life and legacy of Stephen Lawrence SU-50-Lawrence-2-PA.jpg The now iconic family handout photo of Stephen PA The life and legacy of Stephen Lawrence SU-50-Lawrence-3-BBC.jpg Doreen Lawrence on Panorama last week BBC The life and legacy of Stephen Lawrence SU-50-Lawrence-4-GETTY.jpg Doreen Lawrence speaking to the press outside the Old Bailey last week Getty Images The life and legacy of Stephen Lawrence SU-50-Lawrence-5-ALDEN.jpg Tributes lay at the site of the murder in Eltham, south east London Jason Alden The life and legacy of Stephen Lawrence SU-50-Lawrence-6-ANDREW.jpg Neville and Doreen Lawrence, pictured here in 1997, never gave up the fight to bring the killers of their son Buurman Andrew The life and legacy of Stephen Lawrence SU-50-Lawrence-7-BBC.jpg Stephen Lawrence was buried in rural Jamaica, near his great-grandmother, because his mother Doreen worried that a grave in Britain could be desecrated BBC

“For me, 25 years, coming up to 26 years, and this to be still going on, is unbelievable that any family should have to go through this.”

Committee chair Yvette Cooper responded: “I think it’s clear that the experiences that you and your family went through should still be a lesson to all of us, and that’s what I hope our inquiry will continue to pursue.”

Stephen was murdered by a gang of up to six racist attackers as he waited for a bus with his friend Duwayne Brooks in Eltham, southeast London, in 1993.

The bungled original investigation into his death sparked outrage amid claims of racism and corruption in the police.

A public inquiry was set up four years later and in 1999 the damning Macpherson report was published, accusing Scotland Yard of institutional racism.

Two of his murderers – Gary Dobson and David Norris – were jailed in 2012 through the use of new forensic techniques but their suspected accomplices have not been brought to justice.

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When asked if she believes that police in England and Wales are institutionally racist now, Baroness Lawrence said: ”I think in some respects that they still are.

“Nobody wants to be labelled as that, but at the same time it’s undercover, it still exists.”

Sgt Tola Munro, president of the National Black Police Association, said progress on diversity within policing had slowed and there was a “clear lack of representation” in senior ranks.

“It does feel stilted, it does feel at times like it’s stagnated,” he told MPs.

“There have been black people in policing for almost 200 years and yet we find ourselves still at 6 per cent of the police service.”

Sgt Munro pointed out that the Macpherson report called for the proportion to increase by 7 per cent by 2009, and called for positive discrimination to address the gap.