The former News of the World journalist alleged to have put the police officer running the Daniel Morgan murder inquiry under surveillance has dismissed the allegations.
Alex Marunchak spoke out as Scotland Yard said it would undertake a forensic review of all the material in the murder, following 25 years of having failed to bring anyone to justice.
Morgan's murder in 1987 has become one of the Yard's most controversial unsolved killings. After five inquiries, and the collapse of the only murder trial brought in the case, it remains mired in allegations that police corruption tainted investigations over more than two decades.
This week, former Crimewatch presenter Jacqui Hames alleged at the Leveson inquiry that in 2002 Marunchak had commissioned surveillance of her and her then husband Detective Chief Superintendent Dave Cook – who led the last two inquiries into the murder – in order to "subvert" his investigation.
Marunchak – who was on the News of the World newsdesk for 10 years before becoming an associate editor in 1997, with primary responsibility for editing the paper's Irish edition – was also named by the Labour backbencher Tom Watson in a commons adjournment debate as being responsible for ordering the surveillance on behalf of his friend and business associate Jonathan Rees, then a prime suspect for the murder.
The fifth inquiry into the murder collapsed last year, and Rees and two other men were acquitted after the judge ruled senior police had coached one of the main supergrasses in the case, and it was revealed that large amounts of evidence had not been disclosed as a result of the vast material gathered over so many years.
"The person investigating the murder was put under close surveillance by a close business associate of the man being investigated," Watson said.
The MP also claimed that Morgan went to Marunchak with a story making allegations about police corruption a week before he died, that he was offered £40,000 for the story, and that Marunchak also paid the relatives of police officers for information about the Soham murders in 2002.
But in an article in Press Gazette, Marunchak retaliated. "It astonishes me an MP can abuse parliamentary privilege and waste everybody's time by peddling untruths in this way," he said.
He went on to say the MP's comments about his professional dealings with Morgan were "absolutely untrue".
"I do not doubt that Morgan's family now believe he was on the verge of exposing police corruption before he died. If that was indeed a motive for his death, then I know nothing about it."
Marunchak said he had never heard of Daniel Morgan or Southern Investigations until after the murder.
"He never phoned me, contacted or met me, neither directly nor through a third party, by telephone or letter or by any other method."
The first time he had heard Morgan's name was after he was murdered, when his news editor asked him to look into the story, he said.
"Neither I, nor anyone else at the News of the World, offered Morgan £40,000 for his story … we never knew he even existed prior to his murder."
Watson said he had evidence that a police contact had overheard Marunchak claiming he had paid relatives of officers involved in investigating the Soham murders.
But Marunchak said at the time of the murders he was editing the Irish edition of the News of the World and was based in Dublin.
"I never worked on stories about the Soham murders, never wrote copy, nor interviewed anyone. I did not pay any relatives of police officers involved in the Soham murders."
Asked by Press Gazette about the claims made by Hames and Watson that he had put Cook under surveillance, Marunchak said he had passed on to his London newsdesk information from a source that Hames – a former police officer who at the time presented the BBC's Crimewatch programme – was having an affair with a senior police officer on the show.
"I did nothing to check this, because it was of no interest to me," he said. "I passed the tittle-tattle on to the London newsdesk as a bit of gossip, which had been passed on to me, and left it to them to deal with as they saw fit.
"I do not know to this day what checks they carried out, if any at all, or indeed if they did anything about the information. Nor did I ask them to keep me posted with progress or developments. End of story."
Nick Herbert, the police minister, said on Wednesday that the Yard was now carrying out a full forensic review of the Morgan murder. He said the issues of corruption were serious, as was the failure to bring anyone to justice for Morgan's killing.
• To contact the MediaGuardian news desk email editor@mediatheguardian.com or phone 020 3353 3857. For all other inquiries please call the main Guardian switchboard on 020 3353 2000. If you are writing a comment for publication, please mark clearly "for publication".
• To get the latest media news to your desktop or mobile, follow MediaGuardian on Twitter and Facebook
