The exact number of these scalps Mahmood has claimed is unclear. He told the Leveson inquiry into the ethics and practices of the British press that he had brought about more than 250 criminal convictions but an internal investigation ordered by the Sunday Times, where he then worked, found only 94. Mahmood was found to have been "disingenuous" in the evidence he gave to Leveson surrounding his earlier departure from the Sunday Times in 1988 as a result of an act of dishonesty.
Not for the first time, Mahmood bounced back. In October 2012, he was made a star reporter on the Sun on Sunday, the paper that replaced the News of the World - where he made his reputation as an undercover reporter. At the NotW he exposed drug dealers and fake passport scams, as well as embarrassing royals and celebrities for their dubious lifestyle choices.
But he also had reverses.
One of the most sensational was the 2006 collapse of the "Red Mercury" trial, which was based on a Mahmood sting and the allegation that the three defendants were planning to supply terrorists with radioactive bomb-making material. It made a splash story in 2004.
Defence lawyer Stephen Solley, QC, claimed there was a "huge danger of accepting Mr Mahmood's word in respect of any matter".
The acquittal came months after British politician and broadcaster George Galloway had denounced the reporter as an "agent provocateur" and a "disgrace to journalism" after he was invited to dinner at the Dorchester Hotel. The MP, who claimed the journalist posed as a Muslim businessman and made anti-Semitic comments, released a photograph of Mahmood in an attempt to blow his disguise.
At the News of the World, Mahmood was regarded as a scoop machine, claiming about 500 exclusives and named Reporter of the Year at the 1998 British Press Awards for an undercover expose of the views of the owners of Newcastle United.
But in 2003 his sensational front-page story on a supposed international plot to kidnap the children of David and Victoria Beckham was exposed as myth. Once again an expensive public prosecution collapsed, this time as the main witness Florim Gashi was found to have been paid 10,000 ($19,810) by the paper.
Birmingham-born Mahmood, 50, has claimed journalism was in his "blood", as the son of Sultan Mahmood, founder of the first national Urdu paper in Britain.
His methods have been questioned many times but he is finally suspended by his employer, News UK, which has always stood by him. He first donned Arab robes in 1984 to entice prostitutes in Birmingham. He has been dressing up ever since.
- Independent