WHEN Sir Chris Bonington first started climbing as a boy, the moment he touched the rock he knew he’d found something important. What he didn’t know was just how much the rock would give back, that it would relieve his emotional pain and ease his grief. He didn’t know that the rock would make him better.

The best way to explain the effect is to tell the story of the Old Man of Hoy. Sir Chris – undoubtedly Britain’s most famous climber – first climbed the great Orkney sea stack in 1966 shortly after his three-year-old son Conrad was drowned in an accident and, in a way, the ascent helped him get through the sense of loss. Forty-five years later he faced another great crisis: the loss of his wife Wendy to motor neurone disease. But again, there was a chance of relief, almost escape, in climbing the Old Man of Hoy . So he did. At 80 years old.

When I call Sir Chris at his house in the south of France to talk about his life and career ahead of his Aye Write book festival appearance in Glasgow this week, he tells me that in some ways the climb of the Old Man of Hoy in 2014 was not a good idea. “I was very unfit,” he says, “because I’d been Wendy’s carer for 18 months as the disease escalated and it meant I’d had very little exercise and you had to do awkward carries to get her into bed which was bad for my back. So, when I started the Old Man of Hoy I’d basically strained my back anyway.”

Physically, the climb only made things worse. On the way up, Sir Chris slipped two discs and was in agony and even now, five years on, he’s still dealing with some physical problems that were probably exacerbated by the climb. His balance isn’t great, he thinks there’s some nerve damage, and he has a heart condition – all of which means that the inspiring, and moving climb up the Old Man of Hoy in 2014 was the last ever by the man who, among many remarkable achievements, led the first ascent of the south face of Annapurna in the Himalayas and the first of the south-west face of Everest.

Sir Chris would never get maudlin about his health though, and he has no regrets about taking on the Old Man five years ago – quite the opposite because of the healing effect of the rock, the ability of a hard surface to soften grief – first in 1966 when his son died after falling into a swollen river.

“Climbing did help me get through it,” he says. “and it was because of two great friends. In 1966, Tom Patey, who was one of the great wonderful characters of British let alone Scottish climbing and a very good friend, saw that climbing the Old Man of Hoy would help me and it did undoubtedly. And in exactly the same way after Wendy’s death, again when I had an acute sense of grief, Leo Houlding, who had become a really good friend of mine, he saw it in the same way – and it did. It helped me hugely.”

Climbing has helped Sir Chris in many other ways too, particularly in the Scottish hills. In his autobiography Ascent, he describes coming across a book about Scotland’s mountains when he was a boy growing up in Hampstead and how it jolted his imagination in a way he’d never experienced before. The picture that really stuck with him was one of Bidean nam Bian in Glen Coe and its folds of hills and valleys merging into the horizon. It was wild country but it also felt like it was within his reach and he could imagine exploring it.

And so he did. He found older climbers who were willing to show him the ropes, like the legendary Scot Hamish MacInnes, and he found that he was good at climbing and that climbing was good for him. He had not always fitted in at school, but suddenly he was fitting in with men who shared his passion for climbing.

“I was quite a shy person,” says Sir Chris, “and my childhood was quite lonely – my mother worked hard, in advertising, under huge pressure, and had mental breakdowns and god knows what, to give me a really good schooling.

“So I’ve always had that shyness but within the climbing field I found myself at home and, because of my upbringing, although I was socially shy, I was used to talking to adults and I found I was climbing with people who were very much older than me. Like Hamish – he became both a friend and a mentor. I was technically better than he was on rock – I was very good at it – but he was a brilliant ice climber and he was an amazing adventurer – I learned a lot from him. There were both friends and mentors who were older than me and I learned a terrific amount.”

The Scottish hills have not always looked after Sir Chris though – in fact, the closest call he’s ever had, the closest he’s ever come to death was in Scotland, on Lochnagar on the Balmoral estate, when he was climbing with his brother Gerald. All was going well and they were reaching the final serious section of the climb when, all of a sudden, Sir Chris’s ice axes came out of the snow and he found himself being catapulted into space head first.

“I was scared but it all happened so fast,” he says. “I was going head first, hurtling down, and I thought ‘this is it’. The only thing I had time to think about was: is it going to hurt? And then, wham, suddenly I stopped. I think I must have hit the snow, which was about 10 inches deep, so that must have cushioned my fall quite a bit but the runner, a wedge of steel that you jam into the crack, it held. And then I was ok. You then start worrying about how you’re going to get out of the situation but you just get on with it.”

Naturally, because it’s a question you have to put to every climber sooner or later, I ask Sir Chris what the justification is for these dangers and risks and he says it’s not so much a justification as a reason.

“The reason is the strength of your passion for climbing,” he says. “It’s the fascination and drive that fills you – it’s the combination of the risk and the fact that you’re reaching and stretching the limits of what you can possibly do. Innately, it is selfish and I realise that when I think of my friends who’ve died on expeditions but in a way we’re all doing the same thing and they were all there because they shared that same passion for climbing, the same passion for challenging themselves. And if you think about it, the individual who dies, my friends – I miss them but they were going out and doing the thing they absolutely loved.”

Sir Chris would dearly like more young people to discover that love in the way he did when he was a boy and, if anything, he thinks that climbing and adventure has become a little too controlled in recent years.

“Rather than leaning the craft of climbing and devoting their lives to climbing or joining a club and climbing with their peers and exploring and going as far as they can,” he says, “an awful lot of people now want to do, say, the seven summits and they do them with commercial expeditions and they’re guided up them, they haven’t actually learnt the craft of climbing.

“It reflects the society in which we live today – it’s a very busy kind of lifestyle – everyone is having to do an awful lot and everything is made into commodities. You can say I’ll go to Everest and there’s a thousand people at base camp or we’ll go to the south pole or the north pole and you can actually sign up for a trip to do almost anything so you can do what are seemingly very bold things but in actual fact you’re guided all the way through.”

By contrast, Sir Chris believes the kind of adventure that made him happy means an element of risk and he’s worried there are fewer people doing the kind of traditional climbing he always did. “The essential ingredient of climbing and adventure is that element of risk,” he says, “the thrill of going out and taking risks.”

Sir Chris may not be able to take those risks now, but he still relishes one of his first days out in the hills in Wales. Suddenly, everything around him was moving and he realised he was being avalanched and was tumbling down a steep slope. When he got to his feet, he was soaked and exhausted but gloriously happy. He’d tasted what he calls the additive elation of being close to danger. And that was that for the rest of his life.

Career high

Leading the successful expedition that made the first ascent of the South West Face of Everest – it was the fruit of all I had learnt, the planning, the logistics, and the leadership.

Career low

I haven’t really had one. There are downs and ups. You need both and learn from the failures. The loss of my son Conrad was the cruellest.

Favourite music

ABBA - buoyant, joyous, fun

The last book you read

Killers of the King by Charles Spencer, which follows the trial of Charles I. I’ve always enjoyed history.

The best advice you've ever received

Follow your dreams and make them happen.

Your biggest fear

I’m not comfortable in water. It’s ironic – it’s completely irrational but then fears are irrational but when I’m swimming in the ocean I think of all the water beneath me and that scares me. But with climbing I’m a realistic optimist. So I would get us in to desperate situations through my sheer optimism but it’s never occurred to me particularly that I would get myself killed.

Sir Chris Bonington is appearing at the Aye Write book festival at the Mitchell Library in Glasgow on February 7th at 6.30pm. Ascent is published by Simon & Schuster at £9.99