News of the World investigations editor Mazher Mahmood suffered a blow this week after the acquittal of three men charged with trying to buy a "dirty bomb".
The three-month terror trial of Roque Fernandes, 44, Abdurahman Kanyare, 53, both of Edgware, and Dominic Martins, 45, of Stanmore, stemmed from one of Mahmood's trademark undercover stings which earned him a front page in 2004. Undermining his crucial prosecution evidence was central to the defence case.
The defence team trawled back through more than 10 previous Mahmood investigations to find evidence which could undermine him.
Stephen Solley QC told the jury that Mahmood was a "serial deceiver of the courts, of the police, of the CPS and of the Customs and Excise".
He said that he ran his "own personal fiefdom" at the News of the World with little outside control at the paper.
It is the second high-profile courtroom defeat for Mahmood. In June 2003, the trial of five men accused of plotting to kidnap Victoria Beckham after a Mahmood sting collapsed when it emerged one of them, Florim Gashi, was paid £10,000 to act as an informant for the paper.
Gashi was one of the key witnesses in this case and was flown over from Kosovo to testify for the defence team.
Solley told the court that to Mahmood "the story was everything"
and that "as soon as the story was published he wasn't interested in helping the police".
The three men were arrested in September 2004 after apparently trying to buy red mercury as part of a News of the World undercover operation.
Following the verdict, the NoW said: "Our story resulted from a thorough and legitimate investigation by Mazher Mahmood, one of the paper's most senior and experienced reporters whose exposés have led to more than 200 convictions.
"The News of the World involvement in this investigation and subsequent trial was conducted under the direction of senior anti-terrorist police officers.
We are entirely satisfied that the methods used in the investigation were not only wholly proper, but were both authorised and, from an early stage, continued in close liaison with the police.
"The court heard that Mr Mahmood had ‘followed police instructions to the dot' and that he had ‘a very experienced' legal mind.
"This newspaper will continue to pursue any investigation which has a clear public interest."
The result of the trial has led to a renewed attack on Mahmood from journalism professor and commentator Roy Greenslade. In October, Greenslade joined MP George Galloway in calling for Mahmood to "retire", after Galloway was the target of one the reporter's fakesheikh stings.
He said at the time: "There are clear signs that he engages not just in subterfuge, which can be employed in the public interest, [but] he engages in the use of agents provocateurs, inciting crimes to occur, which he can then report on. I believe he dreams up crimes for other people to commit or for agents provocateurs to make them contemplate."
This week Greenslade told Press Gazette: "In the court of public opinion Maz is losing his credibility. I'm pleased about that and I'm sure George Galloway would say the same thing.
"I think what we've done by publishing his picture and highlighting cases like this is making it that much harder for him to operate.
"As the PCC can't do anything, it's up to me and other journalists to police him."
Mahmood is facing another hurdle in February when the Appeal Court will hear Florim Gashi's appeal in a libel case stemming from the November 2002 Beckham kidnap plot story. In April, Gashi was absent when the High Court dismissed his claim, but this time he is expected to appear as a witness.