Sir Ranulph Fiennes lives down a long winding drive at the top of Exmoor. To get there you have to go for miles round tiny, windy lanes before, eventually, you go down an unmarked road to his house. It’s a big cream building with a stream running past the front door and little black sheep munching grass in the field beyond. It’s very picturesque, and rugged enough to suit a man who has been called the “world’s greatest living adventurer” by Guinness World Records.

For though Sir Ranulph (or “Ran” as everyone calls him) is 65, he still hasn’t stopped traversing the globe. This May, after two previously failed attempts, he climbed Everest. He has, over the past 40 years, parachuted on to a Norwegian glacier; gone round the globe, pole to pole, without leaving its surface; walked across Antarctica; discovered the lost city of Ubar on the Arabian peninsula; and run seven marathons in seven days on seven continents.

I expect to meet Ran in his house, maybe with his family — three-year-old daughter Elizabeth and his wife Louise Millington, an endurance horse rider 22 years his junior whom he married four years ago after the death of his first wife, Ginny. However, it turns out that Ran doesn’t live here at all. “My work is here,” he tells me as I meet him in his study, which is in an annexe attached to his building. “But I don’t live here any more.” This seems a shame. His study is magnificent, covered in photographs of past treks and polar expeditions. On the walls there are pictures of him as a young man — very rugged and handsome, all 6ft 4in (1.83m) of him — and photographs of him and Ginny, plus invites to receptions from the Prince of Wales and the Duchess of Cornwall.

He’s obviously a very busy man. I see his diary — it looks manic. He’s in Monte Carlo for lunch with “the Swedes”, and then he’s off to Monkey Island near Heathrow for tea with BMW. Ran tells me it’s how he makes his money. “I do conferences, speeches, lectures, that type of thing. I pack them in so I can spend time at home.”

Home is in Chester. It was there, while giving a talk to the local branch of the Royal Geographical Society, that he met his second wife. “She’s lived there a long time and it’s a beautiful place,” he says. “Louise says it’s much better for education for Elizabeth.”

His daughter is a revelation to him. He didn’t have children with his childhood sweetheart Virginia “Ginny” Pepper, who died in 2004 from cancer. They married in 1970 and were clearly cut from the same cloth. “Ginny was an expert on polar regions,” he says. “We’d lived on this farm since 1984 and we had dogs and sheep and an alpaca. Louise has been kind enough to take on Ginny’s three dogs and the alpaca and three of the black-faced sheep.”

But Louise sounds as if she is also made from stern stuff. “She has a wonderful way with horses,” he says. She was also instrumental in his victory over Everest. On his first attempt, he had awful heart problems. These stemmed from a heart attack he had in 2003 while on a plane sitting at Bristol airport. He ended up having a triple heart bypass.

Louise had pestered him to carry GTN (glyceryl trinitrate) pills, which caused him, he says, “to dilate in all the right places”. He was 40 minutes above Death Camp — Everest’s final camp before the summit — when he had “terrible heart pain, like, I imagine, an anaconda’s hug”. By his third attempt, his wife had him drinking energy gel drinks and recovery potions daily for six months. He believes that these, coupled with her knowledge of why horses can run vast distances (they don’t know where the end is, so they keep going), were key to his success. “I refused to think about getting to the top. I just plodded on slowly,” he says. “And I have a terrible fear of heights.”

That’s not his only problem. He has also had prostate cancer treatment and previous angina attacks. To avoid a surgeon’s bill, he used a Black & Decker saw in his garden shed to cut off the ends of the fingers on his left hand after they were damaged in the Arctic. He has also had a crippling phobia of spiders, which he cured by going to quell insurgency in the Dhofar region of Oman and sleeping outside, surrounded by huge hairy camel spiders. “When I was a child growing up in South Africa,” he says, “I was terrified of creepy-crawlies because I once went to open my mother’s curtains and a huge one fell down my pyjamas.” In Oman he was surrounded by 80 Arab tribesmen. “I couldn’t lose face,” he says.

I think a lot of Ran’s life has been about not losing face. He is not one, I think, to worry about life, the Universe and everything. The psychologist Anthony Clare once said that this was down to Ran’s fear of delving into his psyche about growing up without a father or grandfather.

Both were respected army men in the Royal Scots Greys. His father died in the battle of Monte Cassino in Italy four months before he was born. His grandfather died at about the same time from natural causes. “I spent all my life admiring my family. I have traced us all back for 41 generations,” Ran says, pulling out a huge family tree. “I’m Ranulph Twisleton-Wykeham-Fiennes and I’ve traced my family back to Charlemagne. Most of us have been in armed service. We have served king and country, but not all. Some were poachers.”

He says he always knew he would be the leader of the Royal Scots Greys but, though his mother sent him to Eton he got no A levels. “I took them two more times at crammer in Brighton,” he says, “but I was quite busy watching girls in short skirts so I still didn’t get any.” He therefore could not go to Sandhurst to train as an officer. In fact, Ran talks more of his failures than his successes. “I have failed many times,” he says. “Even though I got up Everest this time, it was a failure in a way. I wanted to make £3 million for Marie Curie and so far, after the three climbs, I’m still short and I didn’t even conquer my fear of heights.”

He doesn’t perceive himself as a great explorer. “The perception of me is that I single-handedly walk across polar ice caps but I never do it alone and sometimes I never achieve my ends at all. I have had to make the decision to turn back many times.” He says that most of his successes have been down to luck. “Luck with the weather,” he says, “luck with the ice.” He doesn’t like to fail, though, not at his age. “I don’t want to be thought of as a geriatric.” He makes himself run every day, even though he finds it boring.

Does his daughter keep him feeling young? Does it relax him doing simple things with her such as painting or baking cakes? “Relax?” he says, almost raising his eyebrows. “I ... I don’t think I’m one for ... um ... you know,” he says. Then his face clears. “We did go on holiday,” he says. “We went to Zambia and followed in the exact footsteps of Livingstone. Louise was five months pregnant.”

He says he doesn’t do beach holidays, though he loves snorkelling, and that he’s cut down on visiting cold places because Louise likes the heat. “We went to Base Camp on Everest for our honeymoon but it wasn’t a good idea. There wasn’t much privacy.” He says that the arrival of Elizabeth has “changed things somewhat”. “Mind you, she’s very game,” he adds. “Quite often, at a weekend, we’ll go over the hills. I’ll be walking with my 14-year-old stepson, Alexander, and Louise might ride, and Elizabeth runs up and down the steep hills for half a mile or more. She’s very fast, but then she gets tired and I have to carry her.”

In the end, you realise that Ran’s life is about adventure. I think he is trying hard, for the sake of his family, to be like the rest of us, but it just doesn’t fit. He’s never going to want a night in with a TV dinner and Strictly Come Dancing. I imagine his family like him that way. When I ask him, for example, about his domestic abilities, he says: “I have changed nappies. I wasn’t very good at it so Louise kindly took over. Alexander is very good with Elizabeth though.”

Really he is happiest when planning another adventure. “I think I’d die of boredom if I didn’t have an idea of where to go next,” he says.

But, in this ever-shrinking world, is there anything left to explore? “There’s always something,” he says. “I’m planning one right now.”

You can bid for Sir Ranulph Fiennes’s Everest kit — boots, helmet and pickaxe — to raise cash for Marie Curie at buyoncegivetwice.co.uk/lots/sir-ranulph-fiennes-everest-kit

RAN’S PERFECT WEEKEND

Mountain hike or relaxed stroll? Stroll with the children

Bond or Sharpe? Bond. I auditioned to be Bond once, but I was told my hands were too big

Safari or snow? Somewhere hot for Louise, so a safari

Savile Row or M&S? I wear what my sponsors want me to. Do they do polar jackets?

Cat or dog? Louise likes cats. She’ll be cross with me if I say dogs

I couldn’t get through the weekend without A hot bath with bubbles. I hate showers. I once went 97 days without washing and all I wanted was a bath