The BBC will tonight reveal the identity of undercover journalist Mazher Mahmood, the "Fake Sheikh" criticised by a judge for lying in the drugs trial of pop star Tulisa Contostavlos.
Mr Mahmood last week lost a High Court battle preventing the BBC Panorama documentary from disclosing his identity.
Refusing the injunction, which would have covered any images taken since April 5 2006 not already in the public domain, judge Sir David Eady said the court had "no reason to restrict the corporation's freedom of speech or editorial discretion".
Mr Mahmood exposed various celebrities and high profile figures while working at the now-defunct News of the World, using his disguise as a sheikh.
The investigative reporter was the key prosecution witness against former N-Dubz singer Ms Contostavlos, but the case collapsed in July when judge Alistair McCreath told the jury at Southwark Crown Court that there were ''strong grounds'' to believe that Mr Mahmood had lied on the witness stand and ''had been manipulating the evidence''.
Mr Mahmood, who denies any wrongdoing and has not been charged, is currently suspended by The Sun and a number of cases in which he was set to be a witness have been dropped by the Crown Prosecution Service while investigations continue.
Last week, Mr Mahmood's counsel Adam Speker told the High Court judge that showing his current appearance in a broadcast which was likely to be watched by millions was intrusive and not in the public interest.
Because of his work, threats had been made to Mr Mahmood, who lived a reclusive life in secure accommodation with 24-hour surveillance and where his neighbours did not know his real identity, he said.
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Mr Mahmood had been filmed in shadow during an appearance on the Andrew Marr show in 2008, photos in a memoir he had written were not sufficient to identify him and various courts, including the Leveson inquiry, had taken steps to conceal his physical identity.
Manuel Barca QC, for the BBC, said that Mr Mahmood's identity was no secret and that the case was not about any fears for his safety but about protecting his livelihood and the shelf life of his professional stock-in-trade.
He said the public interest was self-evident, not least in the context of the Contostavlos trial.
The judge ruled that Mr Mahmood had not discharged the heavy burden of proof under the Articles of the Human Rights Act upon which he relied.
In a trailer for tonight's Panorama, the BBC said it would broadcast interviews with some of Mr Mahmood's highest profile targets and the men who helped him expose them. They allege that the Fake Sheikh was the real crook, using sophisticated entrapment and even creating crimes and fabricating evidence.
Panorama will be broadcast on BBC1 today at 8.30pm.
It's the end of the day at the end of a week that Tulisa Contostavlos hopes she never has to go through again. She sits down, and exhales like a slow puncture. "I've had to stay silent for a year," she says. "I've had to sit back and look like the bad guy, while my whole life was ripped apart."
I have been for decades, and remain, a loyal reader of Private Eye, but a satirical magazine shouldn't lose its sense of humour, as it did when Rebekah Brooks was found not guilty on all counts of conspiring to phone-hack, pay for information from public officials and pervert the course of justice.