Convicted murderer Kevin Lane who was locked up for 20 years for a killing he says he did not commit today asked three Appeal Court judges to declare him innocent.

Joel Bennathan QC counsel for the 47-year-old from Potton, Bedfordshire, said his appeal was based on police corruption and evidence that someone else did it.

The court is being asked to quash the conviction on the basis that it was manifestly unsafe. It is alleged that lane was set up by a bent policeman.

Lane was an amateur boxer in his mid 20’s when he was found guilty at his second trial in 1996 of shooting dead car dealer Robert Magill with a shotgun in Rickmansworth in 1994.

Mr Bennathan told Lady Justice Rafferty sitting with Mr Justice William Davis and the Recorder of Birmingham, Judge Melbourne Inman QC that a jury could not agree at his first trial in 1994 and he was found guilty by a 10-2 majority at his second trial.

He said Lane, who now lives in Kent, was released in January “after 20 years of incarceration”.

He was said to have been one of two “hit men” who carried out the contract killing of Mr, Magill who was shot while out walking his dogs when the killers ran out of woods and shot him five times.

They made their escape in a BMW car which was later found with Lane’s palm print on a black bin bag in the boot.

Lane claimed to have borrowed the car from a friend for family use and said he had handed it back before the killing.

At the centre of his appeal is one of the investigating officers, Detective Inspector Christopher Spackman . He was arrested in 2002 and jailed for four years at the Old Bailey in 2003 for plotting to steal £160,000 from Hertfordshire Constabulary.

He was also found to be wearing a stolen designer watch from another case.

Spackman was in charge of the disclosure of evidence for the prosecution and defence and of handling the exhibits in the Magill case.

Mr Bennathan told the judges that Spackman was also in the cannabis plantation business supplying cannabis to people.

He said his “fall from grace” showed “just how corrupt Spackman turned out to be”.

Officers originally arrested two men for the Magill murder, Roger Vincent and David Smith.

Smith was released and the judge directed Vincent’s acquittal before the trial began leaving Lane to stand trial alone.

But nine years later both Vincent and Smith were jailed for life for a hit man killing outside a Hertfordshire gym which had many similarities to the Magill shooting.

When Lane was released from prison in January he said: “I was innocent from day one when I was in the dock and found guilty. I turned to the jury and said ‘you’ve made a terrible mistake. I never did this.”

There was no evidence directly placing Lane at the murder scene and the weapon used to kill Mr Magill was never found.

As a result of Spackman’s conviction two other defendants in other cases have been freed on appeal.

It is alleged Spackman knew both Vincent and Smith and had “off the record” meetings with them before Lane’s trial.

If successful in his appeal Lane could be in line for compensation up to £1m.

The hearing is due to last two days with judgment expected to be reserved.