If you are rich and famous, and if you have something to hide, you would be wise to read on.

If a man in flowing robes prefixing his name with "Prince" asks to be supplied with, for example, cocaine or prostitutes in return for royal favours, the possibility of him being a reporter really does exist.

Mazher Mahmood, investigations editor for the News of the World, has made a fantastic success of passing himself off variously as an Arab royal, sheik or businessman in order to stitch up alleged wrong-doers.

The former London's Burning star John Alford must rue the day when he offered cannabis and cocaine to Mahmood.

John Alford was found guilty of supplying cocaine and cannabis

In the face of video evidence which the newspaper handed to police after its investigation, the 27-year-old actor claimed in court that he had just been trying to impress the "sheik" who he alleged had offered him £100,000 to appear at a party.

The foundation of the actor's defence (which he conducted himself) seemed to be a cry of "not fair" because he had been "set up" by the paper.

Also to emerge during the trial at London's Snaresbrook Crown Court, was something of Mahmood's own curious lifestyle.

Silhouette

In name only, the News of the World man has a towering profile. He was crowned 1999 reporter of the year at the British Press Awards, and his own newspaper heavily flags up all investigations he masterminds.

His "Toongate" expose - where Newcastle United directors Freddie Shepherd and Doug Hall were revealed to have called Geordie women "dogs" and to have boasted about the large profits they made on replica team shirts - was even advertised by the paper on national TV.

But in other ways, Mahmood guards his personal details - to the extent of appearing in his picture by-line in silhouette.

Allegations made about Johnnie Walker are still being investigated by the BBC

While he is known to News of the World readers by one name, he admits to going by several others.

He said in an interview with the journalists' trade paper, the Press Gazette: "I can go into a party and meet a group of villains who all know me under one of my names."

His parents, themselves reportedly both journalists - his father is a magistrate as well - know him by a different name again.

But that does not stop the death threats pouring into the newsdesk at the News of the World. And on one occasion, Mahmood's parents returned to find their home broken into and hacked with a machete.

The self-styled scourge of the criminal world has let little else of his private life out of the bag.

People in the public eye

It is known that he comes from somewhere in the West Midlands, and that he tried to get work experience for two years running on the Birmingham Evening Mail.

When they turned him down, according to reports, he decided to hit the nationals and worked for three years on the Sunday Times.

He went on to work in production on the David Frost programme for TV-am, and moved from there to the News of the World.

Newcastle United directors Douglas Hall and Freddie Shepherd

Many of his investigations have centred on the alleged misdemeanors of people in the public eye - the BBC Radio 2 DJ Johnnie Walker, for example, recently made Mahmood headlines after a photo taken during an investigation appeared to show him sniffing something through a furled banknote.

The 37-year-old reporter is also adept at infiltrating criminal ranks within the Asian community, and has exposed numerous immigration scams and bogus marriages.

He once told reporters: "I must have had about 25 marriages myself. I jilt them at the registry office door, we get the picture and they get nicked by immigration or go home to wait for The Knock."

Other stories have combined public health concerns with a certain comedy element - most entertainingly, perhaps, when he reported the activities of bakery workers who allegedly not only smoked cannabis on their night shifts, but also laced cakes with more exotic organic matter.

Others still have been deadly serious. An exposé of a council-run children's home in Huddersfield led to the jailing - for sexual offences against children - of the husband and wife team who ran it.

His salary is not public knowledge, but it doubtless reflects the danger his job courts.

His work is meticulously and painstakingly planned out, with no expense spared.

'He's a sheik today'

The Toongate expose involved Mahmood and a colleague flying Hall and Shepherd out to Dubai whilst posing as Middle Eastern businessmen.

The Guardian once reported an anecdote that the News of the World editor Phil Hall arrived at his parking space in Wapping to find it occupied by a Rolls Royce.

He was later told by a news editor that: "Maz hired it because he's a sheik today".

With more than 90 successful prosecutions under his belt, Mahmood and his employers refute accusations that his style of investigation constitutes entrapment.

He acts, they say, not as an agent provocateur, but in the public interest, and within the Press Complaints Commission's code of practice.

In a letter to the Guardian in April last year, Phil Hall wrote: "The News of the World's record on investigative journalism stands scrutiny against any other paper in the country."