YOU don't know Christy McGrath. The name might ring a vague bell or maybe you know a little about him and the campaign to get him freed but you still can't know him.

You can't know whether he's the big softy people from his home town of Carrick-on-Suir describe him as, the one they say couldn't fight his way out of a wet paper bag, or if he's the kind of man who, under the influence of alcohol and ecstasy, killed Gary Walton in a bar fight, even though Walton was considerably bigger and broader than him.

You can't know if he's both these things. You can't know if he's neither.

You can't know if Ann McGrath's recollection of the time her son went as a kid to whitewash an elderly neighbour's wall, and came back with 50p because he wouldn't take the full pound off an old woman, is a pointer to his innate goodness or a mother's own logic, applied in retrospect. Or if Richard Guest - who, while being interviewed by the BBC after winning the 2001 Grand National, looked straight into the camera and dedicated the race to him - knew what he was talking about when he declared that, "Until my dying day, I will not believe that Christy is responsible for this man's death." Or if Gary Walton's sister Sharon Caton knew what she was talking about when she said "McGrath is an evil liar."

Most of all, you can't know what happened on the night of 16 July 2000 in the village of Coundon in the northeast of England because, of the people who do, Gary Walton is dead and Christy McGrath pleaded guilty to killing him.

These are the simplest of facts, yet they tell you next to nothing about this most muddied of cases.

The 'Justice For Christy' banner over the front door means you can't miss the McGrath house in Sean Treacy Park on the outskirts of Carrick. The walls of the front room are covered in photographs of him and his brother Larry in racing action. The biggest of them is of Christy after winning the A�2,756 Black Bottle Conditional Jockeys Selling Handicap Hurdle at Perth in 2000, only his second-ever win. It came on 17 May, two months to the day before an officer stuck his head in the door of his cell in Bishop Auckland police station to let him know that Walton had died.

Ann McGrath wants it made clear how sorry she is for the people Walton left behind him.

"My heart goes out to that family. That man was a son, a brother, a husband and a father and it's an awful tragedy that they lost him. They're victims of a terrible injustice too because they have a right to know what happened to him. I just know it wasn't my son that killed him. I know they think he did and if I was in their shoes, I would probably trust that the police were right as well. They have the right to think that because you're supposed to trust in the police. But that man was strangled to death and it wasn't Christy that strangled him."

This is the heart of the matter. McGrath (29) has never denied having a fight with Walton. He has always maintained that Walton initiated it by threatening him for being Irish and calling him "an IRA bastard, " that Walton came at him with a brick and that what aggression he showed was in self-defence. That aggression, though, manifested itself in wrestling the brick from Walton, hitting him twice in the head with it and then kicking him in the head. He has never denied any of this. The cause of death was given as strangulation, however, a strangulation savage enough to break Walton's neck vertebrae. Not only is McGrath adamant that he wasn't responsible for it, there is no forensic evidence linking him to it.

"To the day I die, " says Ann McGrath, "I'll never forget Christopher's face when the cause of death was given in court as strangulation. He just sat up in his seat with this look of shock on his face. I was sitting looking at him and as sure as my parents are in heaven, his face just fell totally. This was the first time he'd heard that the man had been strangled. But it was all over by then. It was too late to do anything. When I spoke to him later on, he was shaking behind the glass. 'Mammy, I swear on Nana's grave, I did not put my hands on that man's neck.'" That trial took place in January 2001. For the defendant in a murder trial to have gone a full six months without ever knowing the cause of death is just one of the aspects of the case to beggar belief. Another is the fact that when McGrath's barrister sat down with him the day before the trial - after which he changed his plea from not guilty to guilty - McGrath was under the impression that he was being tried for manslaughter and not murder. Had he known he was pleading guilty to murder he would never have considered changing since, to him, it had been a fight he hadn't started with someone he'd never met before in his life, one that had ended up getting tragically out of hand. That wasn't a murder, it was an accident.

But the guilty plea changed everything. McGrath was sentenced to life with the recommendation that he serve 14 years. And with the guilty plea went the possibility of presenting his case in court, of pointing up some of the anomalies in the police investigation and in the prosecution's case. What was, on the