Prince Harry promised to buy a beer for an amputee soldier if he scaled an 18ft wall.
Royal Marine Ben McBean – who lost an arm and a leg in a landmine blast in Afghanistan – made the ascent at the launch of the Khumbu Challenge at the Davenport naval base in Plymouth.
As Ben – who returned home from his tour of duty on the same flight as the prince, with Harry hailing him “the real hero” – climbed the wall, Harry, who is royal patron of the challenge, called out: “No pressure Ben, I’ll buy you a beer if you reach the top”.
Speaking afterwards, 21-year-old Ben – who also hopes to take part in the London Marathon next year – said: “Getting to the top was quite hard, having lost two limbs. But it was do-able. Harry owes me a pint so I’ll be getting that one.”
The Khumbu Challenge will involve five teams from the Royal Navy and Royal Marines of differing mobility and experience tackling a series of Himalayan peaks.
Ben added: “Mostly I’m looking forward to getting with the lads again and being part of a team.
“Getting blown up and losing a few limbs isn’t the end of it – that’s what I’m trying to get people to realise.
“You crack on. That’s what we do in the forces. This is a once-in-a-lifetime opportunity.”
Around 15 of the 90 or so taking part have suffered injury or trauma in Iraq or Afghanistan.
Expedition leader Corporal Steve Perry said: “It means a lot to them. It gives them a focus on their rehabilitation and a sense of belonging to their job, to their colleagues, and to the military family.”
The First Sea Lord, Admiral Sir Jonathan Band, added: “Some of these men have had some tough luck serving their country, now they will be facing this huge mountain, I wish them all the best”.
The launch was the prince’s last engagement before he embarks on selection training to become an army helicopter pilot.