The acquittal of three men accused of plotting to buy a substance which prosecutors claimed could have been used to build a dirty bomb has called into question the tactics used by the News of the World's controversial investigative journalist Mazher Mahmood.
By Chris Summers
Mazher Mahmood is highly thought of at the News of the World, where he holds the title of Investigations Editor and is on a handsome salary.
Mr Mahmood cannot be identified in connection with the case
Not surprisingly really, considering the number of exclusive stories he has brought in over the last 15 years.
Several of them ended up on the paper's front page - such as the exposés of the Countess of Wessex, actor John Alford, Blue Peter presenter Richard Bacon and DJ Johnnie Walker.
Many others were splashed across the paper's centre pages - such as numerous exposés of paedophiles, brothel owners and drug dealers, many of which led to successful prosecutions.
Mr Mahmood won the coveted title of Reporter of the Year at the 1999 British Press Awards.
But his tactics have come under increasing criticism in recent years and more questions will be asked after the acquittal of the defendants in the "red mercury" trial.
Three men - Dominick Martins, 45, Abdurahman Kanyare, 53, and Roque Fernandes, 44 - were acquitted at the Old Bailey on Tuesday.
The trial began in April just as MP George Galloway was succeeding in blowing Mr Mahmood's cover by publishing a photograph on the Respect Party's website.
Several weeks of legal argument took place last year - details of which can only be published now.
Mr Mahmood - smartly dressed and wearing silver-rimmed glasses and beard (which some watching journalists suspected was a disguise) - was questioned by the judge about his methods.
The defence lawyers claimed his tactics and methods undermined the prosecution case.
Stephen Solley QC, counsel on behalf of Mr Martins, claimed a key prosecution witness, Mr B, stood to gain financially and his evidence was therefore compromised.
Mr B denied he was motivated by money and said he only ever asked for "out-of-pocket expenses".
Mr Mahmood said Mr B's motives were partly "family-related" and partly "public duty".
Why he chose to approach the News of the World, rather than the BBC, ITN, the Guardian or the Daily Telegraph, was left unanswered.
The collapse of the case came two years after the trial of several men accused of attempting to kidnap Victoria Beckham.
That case collapsed after it emerged that Mr Mahmood's main informant, Florim Gashi, had been paid £10,000 for the story.
The Crown Prosecution Service was forced to drop the case because it felt Mr Gashi's evidence could not be considered reliable.
The "plot" to kidnap Victoria Beckham was also exposed as fake
One of the falsely accused "Beckham kidnappers", Alin Turcu, later lost a libel case against the News of the World.
Mr Gashi was kicked out of Britain in June 2005 and the red mercury hearing was told that he held Mr Mahmood responsible for failing to prevent him being deported.
Mr Mahmood was asked when he last spoke to Mr Gashi and he said he had received a call not long after this summer's London bombings.
'Tips after 7/7'
He said: "It was shortly after 7/7. He was ringing with tips and he was very angry that he had been deported."
He said Mr Gashi asked for £20 and said he needed money to smuggle himself into Croatia on a bus. "He was very desperate," said Mr Mahmood, who said he did not send Mr Gashi any money.
Mr Mahmood was then asked: "Have you paid Mr B anything in relation to red mercury?"
"No. We have not."
He was asked about Mr B's motives and reiterated that he had been acting out of public duty, adding: "He had been to the police first. If you have financial motives you don't go to the police first."
But the police only acted after Mr Mahmood's paper tipped them off.
The three defendants were arrested by police and the paper splashed the following day with a story headlined "Anti-terrorist cops move in after News of the World uncovers bid to buy radioactive material".
The article began: "This is the chilling moment anti-terrorist police swooped on a gang suspected of trying to buy radioactive material for a "dirty bomb" that could have slaughtered thousands of Britons."
In November 2005, a 27-year-old man was jailed for four months after he admitted selling a fake story to Mr Mahmood and the News of the World about being lined up to be "the fifth bomber" on 7 July.
But what is interesting about Imran Patel's story is the fact that the News of the World splashed on the story without apparently checking its credibility.
On 23 October, they printed a story headlined "We expose Brit extremist linked to evil 7/7 monsters".
The article began: "This is the British-born Muslim terrorist who was lined up to be the fifth 7/7 bomber."
It went on to say: "He says he is friendly with another young Muslim who is close to launching a terrorist atrocity here."
As a result of the story several anti-terrorist detectives were obliged to look into the allegations and ended up wasting 4,070 hours of police time.
Patel was paid £200 for an interview and was promised £5,000 for his story by the News of the World.
Now the failure to secure convictions in the red mercury trial poses further serious questions about Mr Mahmood's methods.