The ranks of the House of Lords will be swollen with the publication of a new list of working peers, including Doreen Lawrence, the mother of murdered 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.

However, there will be no ennoblement for football manager Sir Alex Ferguson, who was hotly tipped for a peerage when he stood down as Manchester United boss after 26 years in May.

Following media speculation that Ed Miliband would make Sir Alex a peer, the staunch Labour supporter is understood to have made clear through friends that he would not want to take up the offer, and no approach was made by the party.

Working peers are expected to attend Parliament regularly, and Sir Alex said at the time of his retirement that he wanted to be free to spend more time with his wife and family.

Mrs Lawrence's tireless campaign for justice for her son led to the Macpherson Inquiry, which found evidence of "institutional racism" in the Metropolitan Police. Two of his killers were finally convicted of murder in 2012.

She has already received an OBE and founded the Stephen Lawrence Charitable Trust to support young people from ethnic minority backgrounds to pursue their ambitions, is a member of the executive committee of human rights group Liberty and has been chosen to sit on Home Office and police panels.

A Labour source said: "Doreen Lawrence is a hero of modern Britain. The strength and courage she has shown in her fight for justice for her son Stephen has had a profound impact on attitudes to racism and policing. Her campaigning has changed, and will continue to change, our country for the better. Ed Miliband believes voices like hers should always be heard in Parliament."

Liberty director Shami Chakrabarti described her appointment as "richly-deserved", adding: "Who can imagine transforming the grief of losing a child into a campaign to reform policing and the wider values of an entire nation? Her calm courage should be an inspiration to everyone."

Deputy Prime Minister Nick Clegg declined to reveal the identities of new Liberal Democrat peers. Mr Clegg told LBC 97.3 radio: "It'll be published any minute now. You can look forward to people, some of whom you won't have heard of, some of whom you may have heard of."