Doreen Lawrence has pledged to speak out over stop-and-check operations being carried out near railway stations in a crackdown on illegal immigration, amid accusations against the Home Office is helping incite racial hatred.
Responding to claims that the checks focus on non-white people, Mrs Lawrence told ITV: "Why would you focus mainly on people of colour?
"I'm sure there's illegal immigrants from all countries, but why would you focus that on people of colour, and I think racial profiling is coming into it."
The mother of murdered teenager Stephen Lawrence, asked if the spot-checks were a cause for her to take up in her new role in the House of Lords, replied: "Definitely so."
Mrs Lawrence told ITV1's Daybreak programme that stop-and-search has always been in the forefront of her mind, and she has campaigned on the issue for years.
She had thought that there was a move away from racial profiling, but then there was a report which said black people were seven times more likely to be stopped, and now these checks are taking place.
The controversy comes as it was revealed that nearly 140 people have been arrested in a wave of raids aimed at tackling people working illegally in the UK.
Immigration enforcement officers have arrested 139 suspected immigration offenders at locations including London, Durham, Manchester, Wales and Somerset and those who have no right to be in the UK face being thrown out.
The move is the latest attempt by the Government to crack down on those illegally in the country, following a controversial advertising van campaign.
Phil O'Shea, who witnessed one of the stop-and-check operations in London, told the Kilburn Times: "They appeared to be stopping and questioning every non-white person, many of whom were clearly ordinary Kensal Green residents going to work."
Writing in The Independent, Dave Garratt, chief executive of charity Refugee Action, warned that the operations could "incite racial tensions".
"Over the last few weeks we've seen some very visible signs of the Government's 'hostile environment' crusade. There have been vans out on the streets with threatening slogans and, reportedly, non-white people being visibly stopped and searched," he wrote.
"The Home Office is responsible for community cohesion. Yet we are increasingly seeing what appears to be hostility towards non-white immigration, which will do nothing but incite racial tensions and divisions within otherwise rich and diverse communities."
A Home Office spokesman defended the tactics: "We make no apology for enforcing our immigration laws and our officers carry out hundreds of operations like this every year around London. Where we find people who are in the UK illegally, we will seek to remove them.
"Immigration enforcement officers conducted an operation at Walthamstow Central Underground station and hub today, based on intelligence, where they questioned individuals to check if they had the right to be in the UK.
"They arrested 12 people who were in the country illegally. Two further people were arrested in follow-up house searches."
Shadow immigration minister Chris Bryant said: "The Home Secretary said that it is unacceptable to stop someone simply on the basis of their ethnicity.
"Theresa May said that someone from an ethnic (minority) background was seven times more likely to be stopped than a white person, and she said that this was wrong and we supported her.
"We must now have immediate reassurance from the Home Secretary that this is the case for immigration enforcement too. With enforcement operations now under the direct control of the Home Office, she must establish straightaway whether the rules preventing racial profiling are being enforced.
"Intelligence-led operations to remove illegal immigrants are to be welcomed. Racial profiling is not."
Mrs Lawrence's seat in the Upper House as a Labour baroness comes after a 20-year fight for justice for her son, who was stabbed to death at the age of 18 in a racist attack in south London.
Her tireless campaign led to the Macpherson Inquiry, which found evidence of "institutional racism" in the Metropolitan Police. Two of Stephen's killers were finally convicted of murder last year.
She told Daybreak that she would also campaign against cuts to legal aid. "If somebody like me didn't have that sort of support, we would never have got those two convictions that took place last year."