Home Secretary Theresa May has said it may be difficult to find out who was responsible for authorising an undercover police officer to spy on the family of Stephen Lawrence.
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 spoke after Labour's Diane Abbott called for an assurance the identity of whoever authorised the Special Demonstration Squad's (SDS) "spy in the Lawrence camp" will be revealed.
But Mrs May suggested 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 said: "I think everybody in this House and across the country was shocked at the findings of the Ellison review, particularly in relation to the question that there was somebody from the
Special Demonstration Squad who was, in the terms that Mark Ellison put it, effectively a spy in the camp around the Lawrence family.
"Every effort will be made to ensure that the truth comes out in relation to this."
Scotland Yard is to request a private meeting with the parents of murdered teenager Stephen Lawrence to share the findings of the criminal investigation into alleged misconduct by undercover officers.
The force is writing to Doreen and Neville Lawrence in order to discuss Operation Herne, the probe into Scotland Yard's Special Demonstration Squad (SDS) - the top secret unit that was up and running for nearly 40 years.
The brother of murdered teenager Stephen Lawrence has said he would agree to take part in a probe into police records following a damning report which found that officers spied on his family.
Metropolitan Police Commissioner Sir Bernard Hogan-Howe plans to appoint an "independent multi-disciplinary team" to search the force's archives for any available evidence for a public inquiry into undercover policing.
Speaking to the BBC, Stuart Lawrence said: "I reserve judgment until I hear who he's tried to employ to try to do this job and I wouldn't mind being part of the team myself to ensure the job is done".
The mother of murdered teenager Stephen Lawrence has demanded the Metropolitan police chief take "decisive action" after a damning report found officers had spied on her family.
Baroness Lawrence has urged Sir Bernard Hogan-Howe to co-operate fully with the judicial inquiry ordered by the Home Secretary following the Ellison review's "devastating" revelations, in a letter seen by the BBC.
A report by barrister Mark Ellison QC published this week found that one of the officers on the original investigation into Stephen's death, detective sergeant John Davidson, may have acted corruptly.
It was claimed that Davidson had admitted having a "corrupt connection" with Clifford Norris, the gangland boss father of David Norris, who was finally convicted of Stephen's murder in 2012.
An undercover officer who allegedly "spied" on the Lawrence family disclosed details concerning the separation of Stephen Lawrence's mother and father, Doreen and Neville.
The officer - known as N81 - reportedly "touched on personal details" concerning the family to the Special Demonstrations Squad (SDS) during the 1998 inquiry into Stephen Lawrence's death, according to the Ellison report.
Neville Lawrence labelled the claims as "disgusting", telling the Daily Mail: "It's unbelievable. They have mocked everything we have done, telling us to our faces that they are listening and things will change, and all the time laughing behind our backs.
"I think they are actually worse than criminals because these officers get paid with taxpayers' money for what they do."
The head of the Metropolitan Police said it is vital police take action on the allegations resulting from the Ellison report into Stephen Lawrence's murder investigation.
The report concluded that a "police spy" had been working within the Lawrence family camp and that one of the officers in the original murder investigation may have acted corruptly.
Sir Bernard Hogan-Howe said: "This sort of allegation shocks me, it shocks my colleagues and it clearly shocked the public so it is vital that we take it seriously and do something about it."
Metropolitan Police Commissioner Sir Bernard Hogan-Howe has told ITV News that it was "pretty awful" to hear the findings of the report into Stephen Lawrence's murder investigation.
"As a professional police officer and then to see the reaction of Mr and Mrs Lawrence who were clearly distraught by what it had heard having lost their son so many years ago, at any level, human or professional, it is pretty awful to hear that list of terrible events," he said.
The head of the IPCC has apologised to the Lawrence family for the police watchdog's part in prolonging the "family's search for the truth".
The chair of the Independent Police Complaints Commission (IPCC) Dame Anne Owers said today that she has apologised to Baroness Doreen Lawrence and Neville Lawrence, parents of murdered teenager Stephen, for the police watchdog's part in prolonging the "family's search for the truth".
Commander Richard Walton has been temporarily moved from his post as Head of the Counter Terrorism Command, SO15, to a non-operational role, following the publication of the Ellison Report, Scotland Yard said today.
The Metropolitan Police said it had voluntarily referred the matter to the IPCC.