There is evidence to suspect one of the detectives on the original Stephen Lawrence murder investigation in London acted corruptly, a major review has found.

There was a high level of suspicion that former Detective Sergeant John Davidson was corrupt both before and after he worked on the police investigation, a report by Mark Ellison QC says.

And there are still lines of inquiry that may be capable of providing evidence of corruption among other officers, although that evidence does not currently exist, the review adds.

Stephen, 18, a would-be architect, was stabbed to death by a group of up to six white youths, in an unprovoked racist attack as he waited at a bus stop in Eltham, south east London, with a friend on April 22, 1993. It took more than 18 years to bring two of Stephen’s killers to justice.

Mr Ellison QC, who was commissioned by the Home Secretary to conduct the review, successfully prosecuted Gary Dobson and David Norris for Stephen’s murder in 2012.

The Ellison report says that, in late July 1998, Scotland Yard’s Anti-Corruption Command held a debriefing with former Detective Constable Neil Putnam, in which he made claims against Mr Davidson.

The barrister says that both the intelligence picture suggesting Mr Davidson was a corrupt officer and the content of Mr Putnam’s debriefing should have been revealed to the public inquiry led by Sir William Macpherson.

“It is a source of some concern to us that nobody in the MPS who was aware of the detail of what Neil Putnam was saying about Mr Davidson appears to have thought to ask him about Mr Davidson’s motives in the Lawrence case,” the report says.After the Macpherson report was published in 1999, Mr Putnam, who was jailed for his own, separate corruption offences in 1998, alleged that, in the summer of 1994, Mr Davidson had admitted having a “corrupt connection” with Clifford Norris, the convicted drug-smuggling father of Stephen’s murderer David.

Mr Ellison says that, while independent corroboration of Mr Putnam’s allegation does not currently exist, there are “outstanding lines of inquiry” that could be investigated, which may change that assessment.

The barrister adds that “it is not impossible to envisage that the inquiry might have been driven to the conclusion that there must have been more to John Davidson’s failure to develop information and evidence in the Lawrence investigation than simply an inappropriate manner and unfortunate unconscious racism”.

Assuming Mr Putnam is available and willing to give evidence, there are reasonable grounds for suspecting that Mr Davidson acted corruptly, the findings said.

Mr Ellison’s report adds: “Other than Mr Putnam’s potential evidence, the material available which suggests that Mr Davidson may have been corrupt in the Stephen Lawrence investigation remains ‘intelligence’ and not ‘evidence’.”

In addition, Mr Ellison said his review has not been able to uncover all material evidence relating to the issue of corruption, adding that it is clear there are “significant areas” where relevant Metropolitan Police records should exist but cannot be found.

The original anti-corruption intelligence database itself cannot be accounted for, the report adds.

Considering whether a further public inquiry should be held, Mr Ellison said the potential for any such inquiry to discover more than his own review has may well be “limited”.

“Fundamentally this is because of the chaotic state of the historical records held by the Metropolitan Police Service,” he added.