The two youngsters could hardly have been any more different; Ann was the studious daughter of a Baptist minister; Dave was a buccaneering young pilot flying crop-spraying planes over the plains of Western Australia.

'Our first date was in an airplane and I was scared stiff,' she said. 'I knew when I first met him that he and I were very, very different people. I guess it was part of the attraction. He gave me the freedom to do what I wanted to do. He always encouraged me.

'I had done very well academically and he never saw that as a threat. He was the only boy I knew at the time who wasn't threatened by it. He just saw that as something special while most boys I knew would comment on it in a negative way.'

Eighteen months later, they were married. Now, 30 years on, Mrs Shaw reflects on what happened as she sits in the Sai Kung restaurant where, in November last year, she helped her husband prepare for the diving mission that would cost him his life.

'There are times when I wish he hadn't done it,' she said. 'But when I look back I still feel I couldn't have stopped him. I loved him too much to tie him down and I don't think that a relationship based on control and restriction is ever going to really thrive.

'I knew it was just part of him being happy, and if you love someone you have to be able to let them go.'

Aged 50, a Cathay Pacific pilot and a father of two grown-up children, Dave Shaw had lost none of his passion for adventure - channelling it into the extreme sport of deep-cave diving.

In October last year, he set a world record by diving 270 metres into an underground cave in South Africa. He stumbled across the body of diver Deon Dreyer, who had drowned in 1994 and sunk into mud on the cave floor. Before returning to Hong Kong, he promised Dreyer's parents he would return to retrieve the body.

'We sat here in this restaurant and ate and we discussed the whole dive and the implications and Dave went through all the safety issues - what he would do if various things went wrong and all the back-up plans,' Mrs Shaw said.

'He was trying to reassure me and then we got on to talking about how we might get a skeleton inside a bag underwater.

'I made the body bag. We actually bought a fishing net from a shop around the corner which I put into the bottom of a Cathay Pacific pilot's sleeping bag. I put a few draw strings along it so that it wouldn't put too much pressure on the fishing net as it came up.'

The conversation was unusual for the pilot and his wife, who never usually heard anything of her husband's deep-diving missions. 'Dave never told me about them until afterwards,' Mrs Shaw said. 'That was the way I wanted it.

'I never liked to watch him work when he was aerial spraying. I was happy that he did it because he enjoyed it, but I didn't want to watch. It was a bit like that with the diving. It was fine to know about it afterwards.'

Every aspect of January's mission - which involved a nine-member international diving team - was meticulously planned. On January 8, Shaw reached Dreyer's body but became entangled in ropes and suffocated, unable to free himself before his oxygen ran out.

In a sombre postscript, Shaw's body days later floated to the surface of Bushman's Cave in the Kalahari desert entwined with that of Deon Dreyer, his final mission accomplished in the most tragic of circumstances.

'What really caused Dave's death was something that he was unable to plan for - the fact that the body wasn't a skeleton,' Mrs Shaw said. 'He tried and tried to find out what state the body was in and most people that were consulted said they thought it would be a skeleton. As it turned out it was solid rather than a skeleton.

'He couldn't lift it when he was first there last year and he thought it was because the tanks were stuck in the mud. When he struck another problem - getting tangled in the rope that he had attached when he was first there in October - he didn't have a way to deal with it. That was the risk. That was the thing he couldn't plan for.'

He could and did plan for his death, however, spending his last wedding anniversary writing out his will - something Mrs Shaw says has made coping with the aftermath of his death considerably easier than it might have been.

She has to some extent psychologically prepared for widowhood by facing the prospect of it for so many years.

'I didn't expect him to die but all my married life I have lived with the risk,' she said. 'I knew when I married him that I wasn't marrying someone stable.' There is a world of difference, however, in dealing with the prospect of widowhood and its reality - the gulf between pent-up relief at a cheery phone call at the end of a mission and the awful knock on the door from a friend bearing the news that she must have dreaded for so long.

'There is the stark contrast between before and now,' she said. 'I have never been alone. I married when I was 19. I have never really had to make all these decisions on my own. Dave was a much more forceful, decisive personality but we always discussed things and made decisions together. Now I have to do everything alone.'

Out of the grief and adjustment, Mrs Shaw has found a mission of her own in a project her husband had embarked on in Hong Kong before he set off for South Africa - finding a site and building a Baptist church for the Clearwater Bay area where he lived.

'It was something he was doing which he felt God had told him to do and it is something I need to keep on with,' she said. 'I find it scary, overwhelming. It is an enormous task. But if it is what God has in mind, it will happen.'

This challenge is one of many Mrs Shaw must now face without the support of the man who has been at her side all her adult life. The prospect does make her question what he did from time to time, she admits.

'There are times when I think, 'Why did you do this'?' she said with a smile. 'I don't regret allowing him to do what he did but I do sometimes think, 'You've got a lot to answer for'!'