A secret Scotland Yard report detailing questions about the conduct and integrity of a police chief involved in the Stephen Lawrence case was not given to the public inquiry into the racist killing, the Guardian has learned.

Lawyers for the Lawrence family questioned former commander Ray Adams at the Macpherson inquiry in 1998 about corruption.

But neither the Lawrence family nor the inquiry panel were given a report by Scotland Yard containing the intelligence and findings of an investigation by its anti-corruption command.

The investigation, codenamed Operation Russell, raised questions about Adams's conduct before the Lawrence case, informed sources say, while finding insufficient evidence to bring criminal charges. Adams insists it exonerates him, and told the Guardian he denies any wrongdoing.

Imran Khan, solicitor for Doreen Lawrence, described the revelations as earth-shattering and said they met the legal standard for the home secretary to order a fresh public inquiry into whether the killers of Stephen Lawrence were shielded by corruption. Richard Stone, a member of the Macpherson inquiry panel, said: "If there had been any sort of documentation, we would have leapt on it. If that had been before us, we would have immediately taken it very seriously and acted on it."

Stone said the allegations were serious and the inquiry should have been told about the Met's report. Scotland Yard said it could not establish if the report had been passed to the Macpherson inquiry.

The inquiry into the murder of Stephen Lawrence in 1993 heard of suspicions from the Lawrence family of corruption among a number of officers. The final report found no evidence of corruption, but the Lawrences say this conclusion must now be revisited. The Met's investigation into Adams began in April 1987, by which time he had risen to become the Met's head of criminal intelligence, in charge of gathering information about major criminals and criminal networks.

It ended with no criminal or misconduct charges being brought against Adams but lists concerns about him, in one instance describing his conduct as highly questionable and unprofessional.

The investigation was carried out by the Met's complaints investigation bureau and conducted by then deputy assistant commissioner Peter Winship. It was triggered by allegations that Adams had taken bribes from criminals and had improper relationships with criminal informants, which he strenuously denied.

During the investigation a detective close to Adams, Alan Holmes, was found shot dead in July 1987. An inquest found he had killed himself, on the eve of Adams being interviewed by corruption investigators. The Met inquiry found Holmes had met Adams during the corruption inquiry and was believed to have passed him details of the allegations and of the investigation's progress.

Some of the allegations against Adams centred on his relationship with Kenneth Noye, a major criminal and police informant. Noye was acquitted of murdering a police officer in 1985, but later convicted of a road rage killing.

One senior police source told the Guardian: "Adams's name came up again and again. The Met never did nail him. It's always embarrassing, especially when somebody is at commander level."

A second report was also not passed to the Macpherson inquiry. Operation Othona was a secret four-year investigation into corruption in the Met ordered by the then commissioner, Paul Condon, in 1993. Part of it featured intelligence and allegations about Adams's conduct, a senior source said, "but not the evidence to take to court".

At the Macpherson inquiry the Lawrence lawyers claimed Noye had a criminal associate, Clifford Norris, whose son, David Norris, was a prime suspect in the murder. David Norris was finally convicted in January 2012 of the murder.

Documents seen by the Guardian show that weeks after the murder, Clifford Norris returned to the Eltham area, despite being on the run, such was his concern about his son. A witness says Norris was confident the police would not arrest him, bragging "he was putting his face up front and nothing was happening".

At the Macpherson inquiry, allegations were also made against a key detective on the first investigation to Lawrence's murder, Detective Sergeant John Davidson. The Guardian has learned that Holmes, a close colleague of Adams, was close friends with Davidson and had partnered with him. On his final day alive Holmes spent most of his time in the company of Davidson, who has denied allegations he was corrupt in the Lawrence murder investigation or during his policing career.

Questions about Davidson's involvement with Norris were first raised in a Guardian article in 2002, with the same allegations being made by the BBC in 2006, and a third news organisation a fortnight ago. Holmes had been interviewed by anti-corruption officers, and was upset by the experience. He was allowed to work on the Met's serious crime command, despite officers knowing he was in a relationship with the wife of a suspected criminal.

Adams retired from the Met in 1993 because of a painful back problem. He later got a job as head of security at NDS, a company controlled by Rupert Murdoch's News Corporation.

On the face of it, Adams was only peripherally involved in the liaison between the police and the Lawrence family during the early stages of the investigation, intervening a week after the murder to sign a letter. But the family had suspicions, detailed in Macpherson's report, which refers to "a notice of allegations and issues" delivered to Adams by the Lawrence legal team, which says: "A potential channel for such influence arises from Commander Adams's previous links with Kenneth Noye who in turn has links with Clifford Norris."

Adams told the Guardian that Operation Russell and the Macpherson inquiry had both exonerated him. Of the Met investigation he said: "The head of the investigation shook my hand at the end of it and said 'you are the only person who's probably told the whole truth'. I only signed a letter, for that I get hammered in the [Macpherson] inquiry, with no supporting evidence at all, not one shred. There is no connection between [Operation] Russell and [the] Macpherson [inquiry]."

Doreen Lawrence said: "I am shocked and appalled by the revelations. Not only must a new public inquiry look at whether corruption existed in the police investigation, but why it was that such critical information was kept from us – Stephen's family. We had a right to know."

The Met said it could not establish if details of Operations Russell and Othona had been passed to Macpherson: "Should any new information arise relating to alleged corruption in the original Stephen Lawrence murder investigation it would be seriously considered."

• This article was amended on 22 March 2012. The original said that questions about Davidson's integrity were first raised in a Guardian article in 2002. This has been corrected.