The News of the World phone-hacking scandal has been something of a boon for the paper's investigations editor Mazher Mahmood. It has diverted press attention from his fake sheikh activities.

But a decision last year by the Criminal Cases Review Commission (CCRC), which has sadly gone unreported for months, has just come to light.

It illustrates once again the dubious journalistic methods used by Mahmood to obtain "stories", and it adds to the catalogue of legal reverses that have occurred due to his use of a specific agent provocateur.

The story concerns Besnik Qema, an Albanian immigrant with British citizenship, who was arrested in February 2005 following a News of the World sting operation masterminded by Mahmood.

It is linked to several other Mahmood stories that relied on "assistance" from Florim Gashi, a Kosovan asylum-seeker whose initial evidence in several trials in the past five years has been discredited.

Qema was contacted via an Albanian-language internet chatroom by a person called "Aurora", who said she was a female. In fact, Aurora was Gashi, and he was operating on behalf of Mahmood.

On the promise of helping Qema to obtain security work for a wealthy Arab family in London, Aurora coaxed him to obtain cocaine and forged identity documents, claiming that it would increase his chance of employment.

The relationship moved from net to the telephone, with Gashi still posing as a woman and continually pressing Qema to obtain the drugs and a false passport.

Despite his reluctance, Qema eventually obliged. He turned up to a meeting at a London hotel and handed over the cocaine and passport to a man he thought was "a wealthy Arab". Within minutes of the hand-over, police arrived to arrest him.

In reporting the arrest, Mahmood's story - headlined "Asylum's Mr Big" - referred to Qema as "a bogus asylum seeker" who was "a drug-pushing pimp" moonlighting "as a people smuggler and arms dealer."

But there was no evidence he was involved in such activities. Mr Qema was a family man, happily married with a young child, who was a director of a security company and worked as a guard for various Albanian dignitaries. He had no previous convictions and had never used drugs.

Within a couple of days of publication, Qema appeared at London's Bow Street magistrates' court and pleaded guilty to charges of possessing and supplying three grams of cocaine and possessing a fake passport.

A month later, at Southwark crown court, he was sentenced to prison for four-and-a-half years. He appealed against that excessive sentence and, in June 2005, the court of appeal reduced it by nine months.

The following year, Mr Qema sought to appeal against his conviction. He said he had been bewildered at the time of his arrest and was unaware of the implications of pleading guilty in what were extraordinary circumstances.

In contesting his own guilty plea Qema ran into a legal problem. There is no automatic right of appeal to the appeal court against a conviction from a magistrates' court if a person has pleaded guilty.

So he served his time and it wasn't until after his release that he was able to contest his conviction through the CCRC.

The commission decided in January last year that Qema's conviction was "unsafe" and referred the conviction back to the crown court in the belief that it would not be upheld.

Qema was lucky enough to be guided in his case by solicitor Paul Butcher, who had previously dealt with a major story involving Mahmood and Gashi.

Butcher had represented three men who were tried on terrorist charges after being accused by Mahmood in the News of the World of plotting to construct a "dirty bomb".

Gashi, having turned against Mahmood, acted as defence witness and said he had helped to entrap the men. In July 2006, they were acquitted by a jury.

This case, and Gashi's part in it, formed part of the argument by Qema's lawyer to the crown court in May last year that his entrapment by the News of the World amounted to an abuse of process. He had suffered from a miscarriage of justice.

There was also a reference to the collapse of a trial in 2003 following a Mahmood story that claimed five men had plotted to kidnap Victoria Beckham. The case was dropped when prosecution lawyers decided that the major witness, Gashi, was unreliable.

In all three cases, Gashi admitted having instigated crimes. Qema's lawyer argued that there would have been no offence without the entrapment.

The crown court agreed and, in September last year, Qema's conviction was quashed when his guilty plea was set aside. The crown prosecution service did not oppose the appeal, stating that they could not comply with their disclosure obligations if there was a retrial.

They did not accept that Mahmood had entrapped Qema, suggesting he too may have been duped by Gashi.

Whatever the case, an entrapped man spent years in jail, as did the three men falsely accused of the dirty bomb plot, as did the five men falsely accused of the Beckham plot.

The Qema case is a reminder that the hacking scandal at the News of the World is just one of the concerns about that paper's journalism. There is a pattern of misbehaviour that should be the subject of a proper investigation into Wapping's Augean stables.

But who will carry out such an inquiry? Rupert Murdoch? I think not. The Press Complaints Commission? Highly unlikely. The Met police? Don't make me laugh. The Commons culture, media and sport select committee? They may have the will but, like the PCC, lack investigative powers.

The judiciary? I guess parliament could set up a tribunal, but I somehow doubt it. Isn't press freedom a wonderful thing?

Sources: CCRC press release/The Times/The Guardian/The Guardian/BBC