Despite calls from Doreen Lawrence, Theresa May is insisting there is no need for a public inquiry at this stage.
Doreen Lawrence has said it will "take a while to gain trust" after she met with the Metropolitan Police commissioner over smear claims.
A memorial service has been held to mark the 20th anniversary of the racist murder of Stephen Lawrence.
Lady Lawrence's elevation to the Lords 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. Holding the Bible in one hand, she said:
"I Doreen, Baroness Lawrence of Clarendon swear by Almighty God that I will be faithful and bear true allegiance to Her Majesty Queen Elizabeth, her heirs and successors, according to law. So help me God."
Lady Lawrence then received a rousing cheer from peers on all sides of the House as she shook the hand of Lord Speaker Baroness D'Souza.
The mother of murdered black teenager Stephen Lawrence has taken her seat in the House of Lords. She will sit as a Labour member of the Upper House using the title Baroness Lawrence of Clarendon.
Some of the biggest names in music have been arriving at the O2 Arena for a charity concert in memory of Stephen Lawrence.
The Unity Concert marks 20 years since the teenager was murdered in a racist attack in Eltham in south east London.
20 years after the murder of Stephen Lawrence, some of music's biggest names will unite for a special concert this evening.
The concert aims to unite communities and bring people of all backgrounds together through the common language of music, raising funds for The Stephen Lawrence Charitable Trust, which helps to develop brighter futures for young people from disadvantaged backgrounds.
Lawyers investigating alleged corruption in the original investigation into the murder of Stephen Lawrence have laid out new key questions that they will aim to answer.
Mark Ellison QC and Alison Morgan, the team that successfully prosecuted two of the black teenager's killers, have been asked to look at claims that undercover officers tried to smear the Lawrence family, and that meetings with his friend Duwayne Brooks were bugged.
They have agreed to give a report to the Home Secretary by December 31, outlining whether there should be further action including criminal charges, and whether a public inquiry should be held into the smear claims.
Today they released details of six questions that they are aiming to answer, the first three covering whether there is evidence of corruption and whether the public inquiry into the investigation was given all relevant information.
The other three are:
- What was the role of undercover policing in the Lawrence case, who ordered it and why? Was information on the involvement of undercover police withheld from the Macpherson Inquiry, and, if it had been made available, what impact might that have had on the Inquiry?
- What was the extent of intelligence or surveillance activity ordered or carried out by police forces nationally in respect of the Macpherson Inquiry, Stephen Lawrence's family or any others connected with the inquiry or the family?
- What was the extent, purpose and authorisation for any surveillance of Duwayne Brooks and his solicitor?
Earlier this week, Metropolitan Police Commissioner Sir Bernard Hogan-Howe urged the former undercover officer behind the smear claims, Peter Francis, to speak to police.
He said: "One of the critical things is to talk to Peter Francis. We've seen him appear on television. We know he's talked to journalists. It would be really helpful if he talked to the investigators because that will help to get to the bottom of it."
However, Stephen's mother, Doreen, has backed Mr Francis's insistence that he will only speak to a public inquiry.
Her lawyer, Imran Khan, said: "He should be giving evidence to a public inquiry, not staying behind closed doors and speaking to police officers. That's the whole point of calling for an inquiry."
Race equality campaigner Doreen Lawrence said she wants to use her House of Lords peerage to "give a voice to ordinary people".
The mother of murdered teenager Stephen Lawrence also admitted she was "nervous" about her new role as a Labour peer.
Doreen Lawrence has changed attitudes and policing in the UK, Labour leader Ed Milband said today after it was announced that she would be made a Labour peer.
Mr Miliband said: "Over the past 20 years, Doreen Lawrence has had a profound impact on Britain and I am delighted that she will become a Labour member of the House of Lords.
"Since the horrific racist murder of her son, Doreen has shown incredible strength and courage as she sought, and continues to seek, justice for Stephen.
"She has changed attitudes to policing and racism in this country and I have no doubt that her strength and determination will be a huge asset to the House of Lords in the coming years."
Labour has hailed the mother of murdered teenager Stephen Lawrence as an "extraordinary voice" after she was named a Labour peer, Downing Street revealed today.
Today Parliament gains an extraordinary voice – congratulations Baroness Doreen Lawrence
JCB boss Sir Anthony Bamford has been made a Tory peer, Doreen Lawrence a Labour peer, and Ministry of Sound mogul James Palumbo a Liberal Democrat peer in a list published by Downing Street today.
The ranks of the House of Lords are due to be swollen with the publication of a new list of working peers, including Doreen Lawrence, the mother of murdered London teenager Stephen.
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.