Speaking outside the Royal Courts of Justice on Wednesday, Baroness Lawrence told reporters: “The Met Police stopped investigating Stephen’s murder five years ago and have done nothing since, despite everything that has been revealed in that time.
“The police must now urgently investigate.”
Stephen, 18, was stabbed by a gang while waiting at a bus stop in Eltham.
Norris, 49, and one other man, Gary Dobson, are the only people to have been found guilty of the murder, with four other suspects never convicted.
Norris’s admission marked the first time any of Stephen’s killers publicly said they had taken part in the attack – but he has refused to name any of the others involved, saying that doing so would pose a risk to him and his family.
Baroness Lawrence said: “This person can name the other killers and says he would love to do so.
“The police must do everything in their power to obtain that evidence and bring all of Stephen’s murderers to justice.
“This man owes me the truth and the Met owe me justice. The police now have no excuse not to act.”