A MURDERER who is serving a life sentence for the ruthless execution of a police informer, has lost an appeal against his conviction.

Ricky Percival was found guilty of the cold-blooded killing of Dean Boshell on the evidence of informant, Damon Alvin, London’s Criminal Appeal Court heard.

Mr Alvin turned Queen’s evidence after he was cleared of killing Mr Boshell.

Lord Justice Rix, sitting with Mr Justice Ouseley and Mr Justice Openshaw, ruled Mr Alvin’s evidence was “highly believable”

The judges also dismissed Percival’s appeal against the 26-year minimum jail term attached to his life sentence.

Twenty-four-year-old Mr Boshell’s body was found on the allotments in Manchester Drive, Leigh, in February 2001.

He had been shot three times, probably with a Colt revolver. One shot was to the back of his head and the other two were fired at very close range.

Lord Justice Rix said Alvin had been questioned over a period of 204 days. His damning evidence against Percival and others filled ten lever-arch files.

Percival, 29, of Cricketfield Grove, Leigh, was jailed for the murder in December 2006. He was also convicted of three counts of attempted murder, relating to a shooting in Southend.

Percival’s lawyers centred their appeal on a sustained attack on Mr Alvin’s credibility as a witness and on shortcomings in the way the trial judge summed up the case for the jury.

The informant was jailed for five years in January 2007 for offences including conspiring to pervert the course of justice.

In his ruling, Lord Justice Rix accepted there had been three “comparatively insignificant errors” in the judge’s summing up, but concluded Percival’s convictions were “entirely safe”.

An appeal against conviction by Percival’s co-defendant, Kevin Walsh, 37, of Shannon Close, Leigh, was also turned down. He was jailed for conspiring to pervert the course of justice, by backing up Percival’s false alibi.