A friend is standing with his eyes fixed ahead, afraid to look down. Dave approaches and sees why. At his feet are the bodies of three children, one six, one three and a ten-month-old baby. The older ones are still clinging to the baby's hands.

"At the time I didn't have all my children myself," he says quietly. "Now two of them are about the same age of the two we picked up. You can't think about it too much. But the memories are very real, as real now as they were then."

The position in which the bodies were found, with the older children clinging to the baby, was vivid evidence that for a few unimaginably terrifying moments the passengers of Flight 103 knew what was going to happen to them. Dave McMullon was to find more such harrowing evidence over the next few days.

A decade on, he finds himself flying over Lockerbie most days of the week. As he looks down, the Newcastle-born airline pilot can make out the cluster of buildings and patchwork of surrounding fields which were the centre of world attention in the days following the outrage.

If it is especially clear, he can see the golf course. That's when the memories of December 22, 1988 are at their most vivid. It is where so many of the bodies were found.

Ten years ago, 36-year-old Dave was serving on an airfield in the south of England as a member of an RAF helicopter squadron, responsible for carrying special forces missions to the world's danger spots.

In the early hours of December 22, Dave and his mates were at a squadron Christmas party. An officer arrived and asked if there were any men who hadn't been drinking. Dave McMullon and a handful of others scheduled for duty later that day stepped forward.

There was a job. "There's been an accident in Scotland," explained the officer. "All we know is that it's bad and they need our support now."

As they piled into their helicopter and hastily carried out the pre-flight checks, large cardboard boxes were loaded behind them. Dave and his fellow crew members wondered what they contained and got on with the job.

On the two-hour flight north, the crew were given very few details. An aircraft had gone down. There was no information about the scale of the accident. "We assumed it was a light aircraft or something," says Dave.

Passing the lights of Carlisle below them, they crossed into darkness over the Border hills. The outline of a ridge approached. As they crested it, they began to realise the size of the disaster.

The roads were packed with the blazing lights of vehicles heading north. "We knew then it was big." Just how big became evident moments later. They saw the section of a fuselage which had ploughed into the town. And fire. Everywhere, fire.

"We could see then it was a Jumbo and we knew that nobody could have survived."

It then dawned on the crew what the cardboard boxes probably contained - body bags.

Dave's Chinook was allocated a landing spot. When the crew climbed out of the machine, their faces were illuminated by the flames where the fuel from the downed jet was still burning. "It was odd," says Dave. "The flames were silent. That has always remained in my mind, the silence of those fires."

Everywhere else was noise as police, fire-fighters and volunteers searched the surrounding area in the hope that someone might have survived. Dave McMullon's helicopter was given the grimmest task of them all.

As the winter sun rose into the sky, four policemen joined the crew of the Chinook. Their job was straightforward enough. They had to locate bodies, put them in the body bags and mark the spot, so they could be collected by the fleet of vehicles working at the scene.

This was when the full horror became clear. Bodies were scattered all around. Some were barely recognisable as human beings.

Others were sitting upright in their seats, some with expressions of terror etched into their faces by death, their bodies apparently unmarked. The soft ground also carried the impressions of bodies which had landed and bounced.

"I tried to convince myself that they looked like waxworks and couldn't be people," says Dave. It didn't always work.

The first body he came across was that of a man who had landed feet first so his body was compressed and still upright. Then there was the body of a teenage boy. "He was fit and good looking," recalls the pilot.

A few yards away Dave found the boy's bag. It had burst open and on top of the contents was a holiday photograph showing the teenager in a bar with his arm around a girl.

"I couldn't think of him as a waxwork. He'd been alive just a few hours before. He'd enjoyed himself on holiday and he was going home with his memories."

Then there was grim evidence that some of the victims had been alive after they hit the ground, having fallen 30,000ft at a maximum velocity of 120mph.

Dave came across the body of a girl in her early twenties still strapped to her seat.

The ground around her bore the marks of her scrabbling fingers. A post death reaction or the last torment? No-one can know.

"But there is the lingering question," Dave ponders. "If I could have got there an hour, two hours earlier, could I have done something . . . obviously I couldn't, but the thought is always there."

Science tells us that many of the victims were certainly alive and probably conscious as they hit the ground.

When Flight 103 exploded six miles above the Dumfriesshire countryside, the passengers would have been blasted into the oxygenless sky and blacked out.

But within a minute and a half, they would have passed into air with sufficient oxygen to enable them to breathe.

The pathologist's report on the co-pilot, who was flying the aircraft at the time of the explosion, shows that he was clinging to his controls until the moment of impact.

As a pilot himself, this information affects Dave McMullon as much as his other memories of Lockerbie.

He knows what was passing through the pilot's mind as he faced a certain death.

"He was fighting for control of the aircraft all the way down. He must have known for all the fall that he was going into the ground," says Dave.

"It's the most terrifying experience a pilot can think of."

For him - like the others involved in the aftermath of Lockerbie - the book will not begin to be closed until the men responsible for the bomb are brought to trial and convicted.

"What happened at Lockerbie makes me angry," he says. "But the families of the victims will never be able to continue with their lives until this case is closed.

"The scars will never heal, but until the case is closed people will always be waiting for the outcome. So will I."

On Monday - the tenth anniversary of the Lockerbie disaster - Barrie and Jean Berkley will travel from their home near Hexham to join other relatives of the murdered in Westminster Abbey. An act of remembrance will begin at 6.45pm. Flight 103 was blown out of the sky at 7.03pm.

Barrie Berkley will find his mind going back to that grim afternoon in 1988 when he answered the phone in his New York office. It was his wife Jean.

She had been watching the TV news at their flat in Manhattan. It was showing scenes from a Pan Am Jumbo crash in Scotland. The plane had been en route to the US.

Which flight was their son booked on, she asked? Alistair Berkley, a 29-year-old law lecturer, had been due to join his parents for Christmas.

Barrie Berkley, then an oil company executive, knew instantly that the news was as bad as it could get. His son had booked on Flight 103.

"Devastating," says Barrie Berkley quietly at his home in Sandhoe as he recalls the torment of emotions.

Memories have been blurred by the shock of the news and Mr Berkley cannot recall whether he contacted Pan Am in the immediate aftermath or whether the airline contacted him.

Two days later, Pan Am flew the Berkleys to London and put them in a Kensington hotel with around 30 other families.

Carers appointed by Pan Am and officials from the US embassy kept the families in touch with what was happening.

"There were briefings about every couple of hours about what the situation was at Lockerbie and whether we could go up ourselves.

"Most people were discouraged from going straight away, being told it would impede the work of the rescuers."

The Berkleys spent several days in the hotel, waiting to hear whether Alistair's body had been discovered.

"We found that people who went to Lockerbie seemed to get priority on getting their relatives remains identified," explains Barrie Berkley, "so we went ourselves."

They were taken around the scene by social workers and told that there was difficulty in identifying the bodies because often they had been separated from passports and other documents.

The Berkleys suggested that forensic experts should go to their son's flat and collect fingerprints.

Barrie Berkley accompanied them and pointed out those things he thought Alistair was most likely to have handled.

Under the circumstances, it seems a remarkably level headed thing to do. "When you're a whole week in a hotel with nothing to do but think about your circumstances, you get pretty desperate," he explains. "We wanted to get out of that hotel. It was pretty traumatic, two or three times a day going to briefings with a lot of other distressed people, just waiting for our sons remains to be identified. We just wanted out of that as quickly as possible.

"So I thought that if they wanted a positive method of identification, fingerprints would be the obvious thing."

The technique worked.

Within a day or two, Barrie and Jean Berkley were told that their son's body had been identified. The couple decided straight away not to go and see him.

"We decided that he was dead and that we'd rather have the memory of how we last saw him alive."

Relatives had been told that while many bodies were remarkably undamaged, some had been ripped apart by the explosion. A number of parents shared the Berkley's decision.

"We were very much discouraged by social workers, police and everybody else from seeing the bodies." A decision which some of the families now regret having taken.

Jean Berkley, 67, is co-ordinator of the UK Families Flight 103 group.

"We are regularly in touch with other people and a number of the family members say they wish they had not been discouraged," says Barrie, 70, "they would have preferred to see the bodies."

Jean and Barrie know that there is a photograph of Alistair's body taken where it was found.

His girlfriend has a copy and has asked the Berkleys if they want to see it. They don't.

"I think all these things are personal. If people want to see the bodies, they should be allowed to."

This issue has become a controversial one among the families of those killed in similar tragedies.

Apart from their work with the Lockerbie relatives, Barrie and Jean Berkley are also active in Disaster Action, an umbrella group for all disasters including Clapham, Zeebrugge and Piper Alpha.

Members give lectures to police and emergency services on the relative's perspective.

"We make it quite clear that if people wish to see bodies they should be allowed to do so. Even if they are traumatised by seeing remains, if that's what they want to do, they must be allowed. For some, it is their way of coping," said Barrie.

For Jean and Barrie - who moved to Northumberland to be near their other son who works in Newcastle - being active in the campaign to get to the truth of Lockerbie is also a way of coping.

"The group is still raising money to do whatever is necessary to find out the truth. There are a number of very dedicated people who want the truth found out and who won't rest until it is however long it takes."

These are the people who will gather at Westminster Abbey on Monday to remember.