Home Secretary Theresa May has suggested it may be difficult to find out who was responsible for authorising an undercover police officer to spy on the family of Stephen Lawrence following the black teenager's racist murder.
But Mrs May assured MPs that "every effort" will be made to ensure the truth comes out in the numerous investigations and inquiries into the police's conduct after Stephen was killed.
She said that Scotland Yard's record keeping on its own investigations into police corruption may make it difficult after the review also revealed the mass shredding of key evidence in 2003.
She spoke after Labour Hackney MP Diane Abbott called for an assurance that the identity of whoever authorised the Special Demonstration Squad's "spy in the Lawrence camp" will be revealed.
Commissioner of the Metropolitan Police Service, Sir Bernard Hogan-Howe, fully supports the call from Baroness Lawrence for decisive action
A senior Met Police officer has been moved from his role following the publication of a report into Stephen Lawrence's murder investigation.
Almost 21 years after Stephen Lawrence was stabbed to death, the Home Secretary has ordered a public inquiry into undercover policing .