THE prime suspect in a 20-year-old murder mystery will today be cleared of killing a schoolboy.

Albert Newman had been due to stand trial for the murder of 13-year-old Colin Maxwell, from Glasgow, who disappeared in 1984.

The boy's skeletal remains were discovered in a back garden in south London in June 1986. He had apparently been strangled with a scarf.

However, the Crown will now offer no evidence when the case is called at the Central Criminal Court in London.

Last night, Colinda Maxwell, Colin's mother, said she was devastated by the latest development.

''I have been through a hell of a lot of trauma for 20 years,'' she said. ''This comes as yet another terrible blow.''

At a pre-trial hearing on Friday, the Crown made it clear that it will be asking for the case to be discontinued when it is called this morning.

The decision ends a two-year ordeal for 56-year-old Mr Newman, who had continued to maintain his innocence.

He was first arrested at his home in Hopeman, near Elgin, Moray, in 2002. However, he was not charged with Colin's murder until May 27 last year. For most of the time he has been on bail awaiting trial.

It is understood that the prosecution case was largely based on a conversation said to have taken place between Mr Newman and a Barlinnie prison officer two years ago.

Since Mr Newman was charged with the murder, police inquiries have uncovered fresh evidence. It is in view of this that the Crown will request that the case be discontinued.

Colin's father left home soon after his son was born in Glasgow on May 27, 1970, and his mother began to live an itinerant lifestyle, flitting between London and Glasgow.

As a consequence, Colin lived most of his life in Rutherglen before moving to London in 1983 to stay with his mother.

At the time she was living at two London addresses and had relationships with two men - one of them Albert Newman. During this period she gave birth to a second child.

Colin disappeared a year after arriving in London on February 19, 1984. He had been sent by his mother to shops in Streatham, south London, to buy food. Mrs Maxwell was never to see her son again.

The following year, Mr Newman was questioned about the boy's disappearance. He admitted he had been staying with Mrs Maxwell at her Streatham address the night before Colin went missing.

He said he had gone for a walk on Streatham Common on the day he disappeared and gave police the names of three friends who had seen him. One is now dead and police considered the other two to be unreliable witnesses. The investigation went cold until June 14, 1986, when Colin's skeleton was found behind a house in Streatham Common North.

By this stage it was impossible to specifically identify the cause of his death, but a forensic pathologist noted that a knotted tartan scarf had been found close to the skull of the skeleton and the coroner at the inquest suggested this may have been used as a ligature.

With no new leads to follow, the case remained dormant until February 2002, when a fresh team of detectives again interviewed Mr Newman.

Mr Newman had a history of alcoholism, leading to him being hospitalised twice.

He has since given up drink and, having remarried in 1996, is said now to have a stable home life and found religion.

Not only is he a committed church attender every Sunday, he takes part in three prayer meetings every week.

Throughout his ordeal his church has stood behind him and he has looked towards it and his family for solace. Today he will put his nightmare behind him when he walks from the Old Bailey a free man.