Ray Walsh celebrated his 40th birthday a few months back. A quiet-spoken Galway man, he says: "The day after my birthday it really hit me and I started asking myself - how long have I been doing this? I started when I was 24. My birthday was a reminder of lost years, I suppose."

"This" is the quest to find out the exact circumstances surrounding the death of his brother, Edward, in London on December 20th, 1985. Officially, Edward (Ebbie, as he was known to his family) was stabbed through the heart with a sword during an alleged dispute over a game of cards in a flat in Notting Hill.

Ray Walsh has serious difficulties believing the official police account of events following his brother's death. He has made a complaint to the Police Complaints Authority in England over what he sees as inconsistencies in their evidence as to what happened on the night his brother died, and how procedures were followed subsequently.

He feels the family's concerns have been dismissed, despite numerous attempts to get clarification from the London Metropolitan Police. All he wants is the truth. "There are too many inconsistencies," he says and so has spent the past 15 years trying to find out what exactly happened on the night his brother was killed.

For Walsh, it's as if by voicing aloud the possibility of regret over these "lost years" he is being disloyal to his older brother, because he says quickly: "I'm not going to have any regrets on my death bed. No matter what - I can say I did my best for my brother. I know if it was the other way around and the situations were reversed he would do the same for me."

Walsh wants an investigation, believing it is ultimately the only way to find out what happened to his brother - but this is something the Metropolitan Police has to date ruled out. He wants to view the contents of the police case file but has so far been denied access to it. At this stage, he is convinced this is more than just bureaucracy.

"If they don't have anything to hide then why can't they at least let the family have access to the file? Surely after 15 years, it's the least our family deserves . .

"These people who have power and make the decisions, ignoring legitimate complaints, they have no idea what they're doing to people . . . Look at the Lawrence family in England . . ."

Stephen Lawrence was a black teenager murdered by a gang of white men in London. His family believed the London Metropolitan Police had not done enough to bring the Stephen's killers to justice and the attempted public prosecution failed. Stephen's family then initiated a civil prosecution which was also unsuccessful. Solicitor to the Lawrences is Imran Khan, who is also Ray Walsh's solicitor, thanks to his contact with Neville Lawrence.

"I had been following the case for a while and I asked to speak to Neville (Lawrence). It took some time to arrange but when he did meet we talked for over two hours. He . . .said there were similarities in the cases. He turned to me at one point and said 'my son was just another black teenager and your brother was just another Irish man'. I was shocked. I was stung by the reality of it."

Walsh is convinced that the Metropolitan Police, while it is publicly making efforts to improve relations with ethnic minorities, still harbours a strong streak of anti-Irish racism and that this has influenced their treatment of the Walsh case. "When I went over to identify Ebbie's body, a detective investigating his death told me and my brother to go to the pub because 'that's what you Irish guys like'," Walsh recalls.

While this may be viewed as a ham-fisted attempt at being friendly, Walsh says he regards it as typical of the insensitivity shown to the family through the whole investigation and subsequent trial.

When he went to identify his brother's body, Walsh was told he couldn't view Edward up close, he would have to do so from behind a plastic sheet. "I wanted to hold my brother's hand but I was told I couldn't because the room was under police seal," he says.

Later, he says, the family learned only by accident that the man accused of Edward Walsh's killing was on trial. No one from the Metropolitan Police had contacted them: "I rang to find out the date of the trial and was told that it had been going on for three days. I couldn't believe it."

Walsh remembers the formalities of the courtroom which seemed to exaggerate the sense of unreality. "My brother was dead and there was no one to speak up for him," he says. It was a separate world with its own language, the barristers on opposing sides were passing notes to each other. There was no police liaison with the family, he says, so he and his uncle just sat in the public gallery by themselves, trying to understand what was going on.

From the start, Walsh had serious difficulty believing the official account of what happened the night his brother died and the more information he unearthed, the more it appeared to be contradictory.

Walsh can readily produce a four-inch thick file containing documents from the past 15 years - and that's just the paperwork he has brought with him for this interview. When he pulls out a post-mortem report or a police statement, it's as if he's presenting evidence, as if he were back in the Old Bailey on that day when he had no official role and so was not allowed to speak.

After numerous false starts, "the case", as Walsh calls it, has finally begun to move forward thanks to the efforts of Imran Khan's law firm. Even the lawyers had a difficult task just to get the Police Complaints Authority to acknowledge that Ray Walsh had even lodged a complaint.

In June last year, Walsh's lawyers sent a list of queries to the Police Complaints Authority for the Metropolitan Police to answer but the authority appeared to have mislaid it and so it took another year for these to be answered. Imran Khan has said in relation to the queries put to the police: "Mr Walsh is looking for straightforward answers to straightforward questions and the concerns of Mr Walsh stem from a seeming reluctance by the authorities to provide these answers."

When asked to comment, the Metropolitan Police confirmed that "correspondence from representatives of the Walsh family have been passed to the Metropolitan Police regarding clarification of a number of facts relating to the murder in Notting Hill in 1985 of Edward Walsh and subsequent events.

"These queries have been addressed by officers in the Directorate of Professional Standards and the Metropolitan Police's response to the queries will be communicated to the Walsh family solicitors."

Indeed, Raymond Walsh finally got his long-awaited response some months ago. He is unable even now to keep the disappointment out of his voice when he speaks about it.

"We had wanted an investigation, what we got were pat answers. This is insulting to the family, it is a patronising response. The police seem to be suggesting that our continuing campaign is due to an inability to come to terms with Ebbie's death."

Among other things, the account by police who attended the scene where Edward Walsh was found and the ambulance crew's accounts appear to differ. Attending officers state they were the first on the scene, but the ambulance crew appear to make the same assertion for themselves. They even differ on the address outside where the body was found - the ambulance crew say No 37 Colville Terrace, the police say No 24. The Metropolitan Police's response to Walsh's complaint does not refer to who was first to find Edward Walsh: instead, it goes through an account of the ambulance call-out.

Walsh's lawyers have now written back to the Metropolitan Police to say the police response to the points of concern was unsatisfactory. The next possible step is an application to re-open the case of Edward Walsh.

Asked about the impact his brother's death has had on his life, Ray Walsh shrugs - it's too big to be put into words. He tried to make a new start in Canada in 1988 but he couldn't let go of what had happened to Edward.

"The case was on my mind all the time. I even contacted a Canadian coroner over there. I couldn't rest, in the end I came back. That's when I realised what was in front of me and there was nothing I could do about it."

In the intervening years, his mother and another brother died while his father was diagnosed with cancer of the oesophagus. Walsh has a long-term partner who, he says, accepts and supports what he is trying to do:

"There are not many who would have stayed considering the quest I was on. She knows everything comes second place to the case. For example, she knows if we have a night out planned and something comes up about the case then that takes priority.

"I have my moments when I'm not able to handle it; when you find yourself jumping out of your sleep at three in the morning or pacing the floor at five."

Ray Walsh has been told by those who love him to get on with his life. He understands their motives but he is angered at the suggestion: "That's all well and good to say but when you've got a lump in your stomach all the time it's hard to get on with other things. That lump has been there for the past 15 years and has never left. I don't know if it ever will but some day I hope it will."