They aim to spend the next few days acclimatising before continuing onwards and upwards.

They have now been travelling for 10 days, after flying to Kathmandu, Nepal, at the beginning of the month.

From Kathmandu the team took a short 40-minute flight on an 18-seat twin-propeller plane to Lukla, a market town at a height of 9,380 ft, where their trek up to base camp – at 17,700ft – began.

From Lukla they trekked through Nepalese villages and the Sagarmatha National Park, staying at small tea houses.

Speaking from Namche Bazaar in the national park, Sir Ranulph said: "Acclimatisation is the key to success for people who aren't big mountain climbers.

"Compared with my attempt to climb Everest from Tibet three years ago and the approach to the base camp on the Tibetan side, the Nepali side is wonderful."

He is making his second attempt on Everest to raise money for Marie Curie Cancer Care's Delivering Choice programme, which aims to give people more choice on where they die.

An exclusive YouGov poll carried out in March among 1,050 people from Yorkshire showed that 66 per cent of people would choose to die at home and further 86 per cent agree that if someone is terminally ill they should have that option.

The expedition has been made possible thanks to Yorkshire businessman Paul Sykes, who funded Sir Ranulph's ascent of the north face of the Eiger, and who has now donated £1m to the Marie Curie cause.

Sir Ranulph says he was moved to support the charity after he lost his mother, his first wife Ginny and his two sisters, the latter three to cancer, all within an 18-month period.

To make a donation to Marie Curie contact Julia Bailey on 0113 2147901 or 07795 564813 or write to her at Marie Curie Cancer Care, Chantry House, Victoria Road, Kirkstall, Leeds, LS5 3JB.