After a seven-and-a-half-year struggle to keep their son's murderer in prison, Brian and Margaret Goodman admitted today they had failed.

They have written a total of 62 letters to Tony Blair, Mo Mowlam, Bertie Aherne, Jack Straw and just about anyone else of stature they could think of in the hope of making sure Paul "Mad Dog" Magee was never again a free man.

But the man who gunned down their son, a special constable, in cold blood and then followed him to finish him off as he tried to crawl away for help, is out, having served just a fraction of his 30-year sentence.

"We have failed after seven-and-a-half years of letter writing," says Mrs Goodman.

"We have lost and he has gone. Our only consolation now would be if Magee were to die or the Good Friday Agreement were to be rescinded putting him back behind bars, but we can't see that happening."

"We have been let down by the system," adds Mr Goodman.

"It's an insult to us and to Glenn. It's an injustice. We have been shuffled from pillar to post and no one would speak to us. They all just pass the buck," he says.

"At one point Glenn actually wanted to join the RUC," says Mrs Goodman with a slight smile. "How ironic that he ended up being killed in Tadcaster. He might well have gone to Northern Ireland and still have been alive today, had he joined up."

Despite the trial and conviction and the passing of the years, the painful memories linger.

"We live this every day," says Mrs Goodman. I can still see Glenn crawling across the road, pursued by Magee. The urge to kill that man is still so strong for me."

Mr Goodman says: "Explaining our anger to those in power is all we can do now. I just pray that Magee doesn't live another 24 hours."

Forgive and forget is not a concept embraced by the couple. "I will never forgive Magee and I will never forget Glenn," says Mrs Goodman.

And their deep-seated hatred does not stop with their son's killer.

Their experience in court during Magee's trial has fostered within them a wider sense of bitterness towards the nationalist cause.

They sat just yards from IRA and Sinn Fein members in court and had to bite their tongues as they were bombarded with quiet taunts by Magee's supporters.

And that bitterness is today all the stronger, knowing that Magee is a free man while their pain continues with constant reminders that their grandson, Tom, aged eight, is without a father.

"He (Magee) is now enjoying life with his family, but I have a grandson who doesn't know who his father is. When we take him on holiday he sees other kids playing with their fathers and he just stands there and looks at them, and I can't help but wonder what he is thinking," says Mr Goodman.

"But I shall continue writing the letters," he says.

"I don't know if I will ever get a reply. It all seems futile now and we are both demoralised, but now he is out there doesn't seem to be much more we can do.

"We want peace in Northern Ireland too, but not at any cost. My son should not be consigned to history as just another statistic."