Mazher Mahmood, better known as the ‘Fake Sheikh’, has begun a long and hard 15-month investigation into anal sex in British jails.

The undercover reporter who targeted celebrities for The Sun newspaper was jailed today for tampering with evidence in the trial of singer Tulisa Contostavlos, who faced drugs charges following a sting operation he conducted.

However, a source close to Mahmood has revealed that this is part of a deep, penetrating investigation into allegations of violent sodomy taking place in the prison system.

“Mazher is passionately committed to journalism, and this is an unprecedented level of deep cover to try and blow this thing wide open,” the source said.

“He’ll be inserted into a hotbed of reported action and will aim to get to the bottom of what is a very sensitive issue.

“Posing as a disgraced former journalist for The Sun newspaper, he’ll be going undercover in a scouse prison to find out whether some of the most unpopular inmates are being targeted for systematic, vigorous bummings.

“He certainly expects there to be a sting at the end of this – which is why he’s packed plenty of sudocrem,” he concluded.

Prison’s warden Gavin Fraser responded today, saying: “We are unable to comment on reports that Mr Mahmood plans to gather some hard evidence in our prison.

“We can say that the fact that he worked for Murdoch’s poisonous rag should not put him at any specific risk here at HMP Liverpool.

“He will be treated exactly the same as any other inmate, and should expect no preferential treatment – although adult nappies and a sewing kit will be available to him at any time, should he come to need them.

“We would, as ever, take allegations of sexual abuse in our prisons very seriously indeed, and there is no way we would turn a brown ey… erm, I mean a blind eye to it.”

?Fake Sheikh? begins 15 month investigation into prison sodomy