The News of the World investigations editor, famed as the undercover reporter who posed as the "fake sheik" for a royal scoop, made a rare public appearance today in a libel hearing centring on an alleged plot to kidnap Victoria Beckham.
Mazher Mahmood, whose identity is always concealed by the paper, took the stand on the fourth day of the action brought by one of the five men the News of the World claimed were plotting the kidnap.
Dressed in a suit and impeccably presented, Mahmood told the court how he had been frightened and unnerved when he went to meet members of an alleged gang he claimed were plotting to seize the wife of footballer David Beckham, intending to ransom her for £5m.
"I was [frightened], yes, " he told the court.
"[The alleged gang leader] Luli was pacing up and down; he was very touchy-feely.
"I would be concerned wearing a video jacket; at the time the video jacket involved had a large camcorder going in your pocket.
"If you are meeting them day in, day out you have to take off your jacket. I would be nervous meeting Luli again wearing that jacket."
The libel action is being brought by a Romanian called Alin Turcu, who the News of the World claimed was a member of a gang.
Mr Turcu and four other men were arrested after the newspaper said it had foiled the plot in November 2002, but a subsequent trial collapsed in June 2003 when it was ruled that the paper's informant was an unreliable witness.
The News of the World has, however, stood by its story and claims its allegations were "true or at least substantially true".
Mahmood said today he and his undercover reporters had not prompted the gang to talk about a proposal to kidnap Mrs Beckham but were obtaining evidence of a plot that had already been hatched.
He argued that it would be "unethical" to put a crime into the minds of others.
"This gang were involved in a variety of criminal activities and amongst them was kidnap," he said.
"It was totally correct for me to get involved and tap into that gang. There are no rules that say you cannot do this or cannot do that - but it's unethical to incite a crime, to get someone to do a crime that did not exist.
"These were people who had previously kidnapped; they were kidnappers. They were drug dealers; they were involved in forged documents.
"These were criminals and there was nothing wrong tapping into these criminals."
He added: "It would not be unethical to infiltrate a gang involved in a variety of crime and in this instance they would be involved in kidnap."
Mahmood said the plan to kidnap the former Spice Girl had "evolved" from a separate plan to abduct an Arab prince.
"The initial target was a prince called Abdullah," he said.
"It clearly did not come from [Floirim] Gashi [the News of the World's informant]. It was Luli's suggestion.
"It was Luli who said he knew somebody who was a hairdresser that Victoria Beckham visited, which presumably provided him with the idea of kidnapping Victoria Beckham."
Mahmood described how he had become convinced that the alleged plotters were planning a genuine crime.
"They recruited one of our undercover reporters; they had firearms; they were involved in serious other crimes.
"This helped the picture of them as criminals planning the kidnap of Victoria Beckham. The evidence was stacking up. There were conversations with all these individuals recorded on tape and some of it not on tape. The evidence was piling up. As time went along I came to the conclusion these guys were serious."
He dismissed the suggestion, put to him by Mr Turcu's advocate, David Price, that the taped conversations merely showed "idle banter".
He told the court: "No, it's not my belief at all. I've never come across a bunch of criminals with the form they have got talking like this about a crime they did not intend to commit."
He added: "You might get a criminal bragging about X, Y, Z but you would not get five different people of this stature who would discuss matters like these - it just would not happen, I find that very difficult to believe."
He pointed out that at one stage in one of the tapes the alleged gang leader was seen to be trying to hush other members of the group when they were talking about the plot in a restaurant.
Mr Price asked Mahmood whether he had targeted the gang because they were unlikely to be able to sustain a libel claim should the story turn out to be untrue.
"That's completely and utterly untrue," Mahmood replied.
The journalist said he was "dubious" when he first heard about the plot but was later convinced it was genuine.
He said that kidnap was a common crime in certain parts of the world, particularly former eastern bloc and Asian countries, and that it was increasing in Britain.
The alleged gang he claimed was involved in a Beckham kidnap plot had shortly before this time detained an eastern European somewhere in south London, he said.
He said he had passed details of this abduction to the police and was "frankly quite disappointed" that they had not pursued it further.
Mahmood is continuing his evidence this afternoon and the trial is expected to last throughout next week.
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