Infamous for often reporting undercover posing as a wealthy Arab dressed in robes and a keffiyeh, his evidence has helped secure convictions in several high-profile cases including on drug charges involving celebrities and sporting figures.
His methods, though, have been criticised and several of his targets have complained of entrapment.
In July, a case against pop star Tulisa Contostavlos, who was accused of offering to procure cocaine for Mahmood, collapsed after the judge said he had “strong grounds to believe” Mahmood had lied at a hearing before the trial started.
A Crown Prosecution Service spokesman said this had prompted the body to look again at convictions secured through evidence supplied by Mahmood.
“We are now considering past cases which resulted in a conviction in criminal courts in England and Wales based on evidence provided by Mr Mahmood, and have identified 25 cases,” the CPS said in a statement.
In the Contostavlos case, Mahmood had posed as a wealthy film producer offering the former talent show judge a major role in a Bollywood film.
Mahmood was suspended from The Sun on Sunday newspaper, owned by Rupert Murdoch’s News UK British newspaper arm, in July following the trial’s collapse.
He had previously worked for Murdoch’s News of the World newspaper before it was shut down in the wake of the phone hacking scandal.
The Sun on Sunday and parent company News UK were not immediately available to comment.
Mahmood’s story on cricket spot-fixing in 2011 led to the convictions of three Pakistan players for their involvement in the betting scam.
His investigative work earned him a Reporter of the Year award at the 1998 British Press Awards. -AFP