North Londoner Noch Spitzer was the Camp Simcha “big brother” to Marc Lebe, who died last year, aged 21, from Duchenne muscular dystrophy.

Around the anniversary of his death, Mr Spitzer saw an advert for the charity’s Yosemite challenge in California. To him, taking part seemed a fitting way to both honour the memory of an “inspirational” young man and raise funds for Camp Simcha’s volunteer programme so “others can get the amazing opportunity I had as a volunteer”.

The 30-year-old and wife Talia were among 13 adventurers who trekked to the highest peaks of Yosemite National Park — climbing more than twice the height of the Empire State Building — to raise £45,000-plus.

“The atmosphere was special and the scenery was spectacular,” Mr Spitzer recounted. “I had photos of Marc with me which I looked at every morning to remind me of my motivation.

“We attracted a bit of attention as we walked in our matching T-shirts. What was amazing was that when people asked us what we were doing, many then reached into their pockets to give a donation.”

Also among the trekkers were David Berke and his wife Dr Shelley Jacobs, participating to mark their 50th birthdays. Dr Jacobs has supported Camp Simcha as a member of its medical advisory panel and as the doctor in residence on one of its annual retreats.

“As I trekked I thought about the Camp Simcha families I have got to know and some of the children who are sadly not with us anymore,” she said.

Lez Issler from Manchester found “the mental challenge as hard as the physical. There were points when you were so exhausted but then you got to the top and saw the view and it was all worth it. As a group, we enjoyed a sense of achievement.

“We also all knew we were doing it for an important cause.”