Few people can climb Mount Everest and call it a failure, but David Tait is one of them.

Looking fit and relaxed, the 44-year-old hedge fund manager looks every inch the City high-flier as he greets me warmly with a firm handshake and invites me into his Cobham home.

But since returning from his attempt for an unprecedented double traverse of Mount Everest, he has had to get used to an unfamiliar feeling: failure.

Climbing the 8,858m peak of the world's highest mountain then descending, retracing his steps and doing it all again was always going to be a big ask. But for someone so used to success, how did the reality finally dawn that this was a summit too far?

David begins his tale shortly before reaching the summit on June 15, with his Sherpa climbing partner Phurba Tashi.

He said: "When we were at Advanced Base Camp (ABC), we were acclimatising and reading books, while the Sherpa were beavering up and down the mountain.

"I had seen this before - but it never really dawned on me quite how embarrassing and humbling it was. Phurba and his team laid the ropes at the summit and had them ready by April 30 - which was the earliest ever recorded.

"He came all the way down to ABC at 6,400m in six hours - I did the same in 2005 in 13 hours. I'm fit but these guys are just in a different world.

"When I saw them come to camp on April 30, I was fully aware that I would be accompanied by this man (Phurba) on my double traverse, and I had these reservations in my mind.

"I was thinking: Who am I kidding? I can do the equivalent of him, but I can't do it anywhere near as fast'."

This nagging doubt, about which David had worried for months, persisted throughout the journey, which began on March 29.

The physical aspect was not the issue. Throughout the lonely freezing hours his mind was occupied by the morality of claiming a record he had no right to.

He continued: "I could have hung in there long enough to do it, but when it comes to a world's-first you generally assume it's a meritocracy - that the person with the greatest stamina and speed is the person who has the record.

"The Discovery Channel was going to film this and look for anything controversial to appeal to the general public.

"I thought about my work in hedge funds, which haven't had a great press recently. I mean, how was that going to look? Hedge fund manager pays sherpa to take world-record' - you can just see the headline.

"I felt as though I was setting myself up for a monster fall, and it would also have conflicted with everything I was trying to do for the charity."

Even so, David has now raised close to £500,000 for children's charities through his Everest ventures.

Sponsorship from the latest climb has been donated to the Children in Court appeal, which is pushing for victims of child abuse to be able to give evidence electronically in court.

David suffered from such abuse in his youth - during our conversation, it became clear it has affected his self-esteem throughout his life.

Aborting the challenge, he said, helped him discover a far more liberated state of mind. He said: "It was a cathartic moment for me. I had a vision of becoming a world's-first at something simply because through the child abuse issue you always feel second-rate.

"I was driven to achieve these things to prove to myself that I wasn't half a person. But I've realised that I'm not afraid of saying that I came second - I have my three successful summit attempts and that's fine for me."

David has already written several chapters of a new book about the double-traverse attempt and hopes it will be ready this year to coincide with the Discovery Channel's programme.

And for all the fanfare traditionally afforded to the task of climbing Everest, this one compelling aspect about David Tait stands out above everything else.

For him, the real thing led to a far more profound achievement - the scaling of his own personal Everest after years of self-deprecation.