'Fake Sheikh' Mazher Mahmood and driver found guilty of perverting course of justice in collapsed Tulisa trial

Prosecutors said Smith and Mahmood had a 'vested interest' in Ms Contostavlos being convicted

Mazher Mahmood arrives at the Old Bailey (Reuters)

A former undercover journalist known as the “Fake Sheikh” is facing jail after being found guilty of tampering with evidence in a drugs trial.

Mazher Mahmood, 53, was convicted at the Old Bailey alongside his driver, Alan Smith, 67, in relation to a case involving pop star Tulisa Contostavlos.

They were both found guilty of plotting to pervert the course of justice by conspiring to suppress evidence at the former N-Dubz singer's trial. Ms Contostavlos had been accused of supplying cocaine but the case, which came about after a story published in The Sun on Sunday, was thrown out of Southwark Crown Court in July 2014.

Since the trial collapsed, a number of criminal cases – in which Mahmood was due to appear as a witness – have been dropped and some convictions are being reviewed.

For over a quarter century, Mahmood worked as an undercover reporter for the The Sunday Times, The Sun on Sunday and the now-defunct News of the World. Helped by Smith, he became known as “King of the Sting” but has been suspended by News UK.

Ms Contostavlos always maintained her innocence and following the collapse of the Southwark trial insisted: "I have never dealt drugs and never been involved in taking or dealing cocaine.

"This whole case was a horrific and disgusting entrapment by Mazher Mahmood and The Sun on Sunday newspaper."

The singer had been accused of arranging for Mahmood to be sold £800 of cocaine by one of her contacts following a sting for the newspaper in May 2013.

During a meeting at the Metropolitan Hotel in London, Mahmood posed as a film producer and plied Ms Contostavlos with alcohol as they discussed an acting role alongside Hollywood star Leonardo DiCaprio.

As Smith drove the former X Factor judge home to Hertfordshire, she allegedly spoke about a family member who had a drugs problem.

When he was interviewed by police about the journey more than a year later, Smith recalled the anti-drugs conversation. But a day later, after speaking to Mahmood and emailing his draft statement, the singer's anti-drugs comments were removed, the court heard.

At a pre-trial hearing, Mahmood denied being an “agent provocateur” or that he discussed the statement with Smith.

But when he was questioned at length in the trial, Mahmood appeared to concede he had talked to Smith about what Ms Contostavlos said about drugs in the car.

Prosecutors said Smith and Mahmood had a “vested interest” in Ms Contostavlos being convicted.

This sentiment was echoed by her lawyer, Ben Rose, who said: "The real scandal in this case is that Mahmood was allowed to operate as a wholly unregulated police force, ‘investigating’ crimes without the safeguards which apply to the police.

"As a journalist, he was able to rely on unnamed ‘sources’ and was not required to give full disclosure of his investigation to the defence. As Tulisa’s defence lawyers, we were prevented from properly testing the strength of his evidence.

"It was obvious from the outset that Tulisa should never have had to go to court. If Mahmood’s evidence had been properly stress-tested instead of accepted wholesale by the CPS, we are confident it would have come to the same conclusion.

"Investigative journalists do important work, but Mahmood clearly went too far.

"It is shocking that Mahmood was able to get so many convictions despite mounting evidence of his duplicity. Chronic underfunding might explain why those involved in the criminal justice system are unable to resist the lure of his pre-packed prosecutions, but everyone involved failed to grasp the extent of his dishonesty.

“Mahmood’s actions brought his profession into disrepute and ruined hundreds of lives in pursuit of better circulation figures."

A News UK spokesman said: "We are disappointed by the news that Mazher Mahmood has been convicted. We do not have further comment at this time."

Mahmood and Smith will be sentenced on 21 October.

Press Association contributed to this report