Unless you have had your heart torn out of your chest you won't know how it feels to have a child murdered by terrorists.

John Maxwell was devastated when the IRA killed his 15-year-old son, Paul, with a bomb on board a fishing boat on a sunny Bank Holiday weekend by the seaside at Mullaghmore 30 years ago, on August 27, 1979. The intended target, 79-year-old Lord Louis Mountbatten, a cousin of the Queen, also died in the blast alongside one of his twin grandsons, 14-year-old Nicholas Knatchbull. Another passenger on the boat, the 82-year-old Dowager Lady Brabourne, died the day after the attack.

Victims' relatives react differently. There are those who feel their lives have been destroyed and never recover. Others become embittered or wallow in self-pity. And there are those resilient souls like John Maxwell who manage to patch their lives back together and become an example to the rest of us.

John had a lot of patching up to do. I remember meeting him just hours after the explosion. As a still wet-behind-the-ears cub reporter I had been sent to Mullaghmore to cover what was the biggest news story in the world at the time. I had driven out the coast road to where small fragments of wreckage from Lord Mountbatten's boat, Shadow V, drifted in the sea close to the rocks and trawled the village for anyone from Fermanagh who may have seen what happened. The word was already out that Paul was one of the victims so when I suddenly spotted his father's familiar face coming towards me I struggled for something to say other than offer my condolences. He was distraught and distressed and struggling to make sense of what had happened; a frail shadow of the powerful Ulster rugby player who had coached me in the game and shared my passion for fishing. It was as if the spirit had been wrenched from him, but later that very afternoon it returned, and the anger over Paul's death disappeared.

"I lost the head for a while and started ranting and raving," he recalls. "I was shouting about Paul being an Irishman; what advantage was there in killing your own? What was to be gained from killing an old man?

"Then the anger just left me and I've never felt it since. It just left me like a flash. It suddenly hit me what had happened," he adds.

"I felt something in the pit of my stomach which wasn't pain but a very strange feeling. Utter devastation. I remember thinking nobody should ever have to go through this. I said to myself, for the rest of my life I'm going to do as much as I can to make sure this kind of thing doesn't happen, as far as any single person can do anything," John explains.

"So I said to myself, be careful what you say from now on because you might exacerbate the situation. I've never been in favour of an eye for an eye. I'm no saint but that was what I thought at the time and I have felt that way since," he explains.

"You never get over something like that completely," he admits. "I still get flashbacks.

"When it happens to you, it changes your whole outlook," he adds.

Some people still ask why, 30 years on, there is no memorial to the victims in Mullaghmore. But there is a memorial to Paul, in Enniskillen. The Erne Integrated Primary School is a living memorial to the schoolboy whose father believes that by educating children from different backgrounds under the same roof we can defuse the sectarianism which has become almost part of the genetic make-up of people in Northern Ireland. Motivated by his own personal tragedy and spurred on by another IRA bomb which murdered 11 of his fellow citizens at the Cenotaph in Enniskillen on Remembrance Sunday 1987, John became one of the driving forces behind integrated education in Fermanagh.

"You can't quantify it. You can't measure the benefit of integrated education. But there is an interaction between people in both communities, children and their parents, and they get to realise that people from the so-called 'other side' don't have two heads," says John.

Born above his father's chemist's shop beside the Cenotaph in Belmore Street, Enniskillen, and educated at Portora he qualified as a teacher at Stranmillis College in Belfast before going on to Loughborough College in England to specialise in Physical Education. He taught in Belfast for a year before returning to Fermanagh to take up a lecturing post at Enniskillen Technical College, which later became Fermanagh College of Further Education and is now the South West College. He retired in 1989.

He and his first wife, Mary, spent their summer holidays with their three teenage children, Donna, Paul and Lisa, at the family's holiday cottage at Mullaghmore. It was there that Paul got a job on Lord Mountbatten's boat. The Queen's cousin regularly spent his holidays at Classiebawn Castle beside the seaside resort.

John had concerns about Paul working on the boat but was reassured when, on a late night visit to the harbour, he was challenged by gardai keeping an eye on Shadow V.

He recalls the day his son died in harrowing detail.

"It was a beautiful morning. The summer had been a bit like this summer where there was no sun at all but that was a fantastic day," he remembers.

Paul went off across the fields from the cottage to the Classiebawn Castle where Mountbatten and his guests were staying.

"I went down to the village to get a paper and I saw him in the boat getting it ready for going out. I waved at him and he waved back and that was the last contact I ever had with him," John recalls He was sitting at the back of the family cottage enjoying the sun when he heard the blast as the 50-pounds bomb that had been planted on the boat the night before exploded.

"I kind of knew what it might have been so I got into the car and I drove pretty frantically around the headland because I knew the boat took the same course every day. I went down the hill to the cliff edge and the first thing I saw was bits of debris, bits of wood floating out in circles and then a lot of boiling and bubbles in the sea," he says.

"I didn't know what to think at that point, I didn't know what boat it was then but I suspected it might have been that one. A lot of the other boats that were out at sea came in, honing in on where the boat had gone down to see what had happened.

I found out afterwards that they had been picking up bodies and people who were still alive," he adds.

"I was almost sure at this stage it was Mountbatten's boat. I became kind of frantic and I was for climbing down the cliff but a guard appeared on the scene and he persuaded me not to do that," explains John.

He rushed down to the harbour where, amid the chaos, an acquaintance told him his son was alive and well and in the Pier Head Hotel.

"At that point I was delighted. I went in to the hotel and they showed me this fella lying with blood all over him but it was not Paul," adds John.

It was one of Mountbatten's twin grandsons, 14-year-old Tim Knatchbull, who survived the blast.

Eventually John discovered his son's body had been taken from the water by a fisherman friend.

"I went on to the boat and found him. The explosion must have blown his shirt off because his upper body seemed to have nothing on it. It was still warm and I thought he couldn't be dead but he was. I understood since that he died instantly," he adds.

It later emerged that two hours before the explosion and 70 miles away, gardai had arrested two men, Thomas McMahon and Francis McGirl, suspected of being in a stolen car. They had planted the bomb and fled, leaving it to a third IRA terrorist to detonate the device by remote control at 11.39am when the boat was 200 yards from the harbour.

Both men were tried for their part in the murders. McGirl was acquitted and died in a farming accident in 1995 when the tractor he was driving toppled over.

Flakes of green paint from Mountbatten's boat and traces of nitroglycerine explosives were found on McMahon's clothes and he was convicted of the four murders.

John says he felt a sense of relief when McMahon was convicted. However, he also publicly supported his 1998 release, after 19 years in prison, under the Good Friday Agreement, something he admits was "hard for me to say" at the time.

He has tried unsuccessfully to meet his son's killer.

"I've made two approaches to McMahon, the first through a priest, who warned me in advance that he thought there wouldn't be any positive response. And there wasn't. I have some reservations about meeting him, obviously - it might work out in such a way that I would regret having made the contact. On the other hand, if we met and I could even begin to understand his motivation. If we could meet on some kind of a human level, a man to man level, it could help me come to terms with it. But that might be very optimistic. McMahon knows the door is open at this end.

"I think I would put a question to him directly, along the lines of...'If I had killed his son, for whatever reason, how would he feel about it? Would he be capable of putting himself in my shoes, to look at it from my angle?' I'd be interested to know how he would reply to that," says John.

McMahon has never publicly discussed his role in the bombing. However, the year before his release from jail, his wife Rose, a former Sinn Fein councillor and mayor of Carrickmacross said: "Tommy never talks about Mountbatten, only the boys who died. He does have genuine remorse. Oh God yes." McMahon served the first 13 years of his life sentence in the IRA wing of Portlaoise. He and 10 others, armed with guns and explosives, failed in an attempt to escape in 1985. Three years later, he fired a shot from a Browning pistol smuggled into a holding cell at Dublin's Four Courts. In 1992 he claimed to have turned his back on the IRA. However, the now 61-year-old is understood to remain heavily involved in republican politics in his home town of Carrickmacross.

John hopes that those behind the attack that claimed his son's life have changed.

"I understand the IRA Army Council sanctioned it and on that I think you would have had some of our present politicians," he says.

"I have to give them the benefit of the doubt. They must have changed to some extent or they wouldn't be entering the kind of agreement they have entered," he adds.

"If you look at the thing from the point of view of the country, you have to go along with it and it is better that these guys change later than never," John concludes.