My First Job: Explorer Sir Ranulph Fiennes was an SAS officer

'A poisonous spider landed on an orderly'

Captain Fiennes of the SAS had come to the end of the road. After a five-mile hike across country to the dam, he and his band had set the time-fuses on the high-explosives, which were now blowing up in sequence. But there had been a tip-off, and when they got back to their cars the forces of law and order pounced. He was in for the high jump and out of the SAS.

Sir Ranulph Twisleton-Wykeham Fiennes has come a long since the summer of 1966 - via both Poles, in fact. In March, he plans to conquer the icy Eiger's north face - and his own vertigo - in aid of Marie Curie Cancer Care (a charity highly commended by anyone who has benefited from their nurses' care of a dying spouse). He was not always quite such a respectable a figure.

After three years as an officer in the Royal Scots Greys, "Ran" applied in 1965 to the Special Air Service. To weed out the weedy, the SAS painted the blackest picture of what lay ahead (a practice he now employs when recruiting for his expeditions). At its Hereford base, he underwent a gruelling selection process. "I discovered there were over 100 soldiers and more than a dozen officers. Two officers got in and I think eight soldiers." He was one of those officers. What did it involve, being in the SAS?

"I can only tell you about the training," he replies diplomatically. So he was involved in actual military operations too? "I can only tell you about the training," he repeats. What he is allowed to tell us is frightening enough: "Jungle training, advance explosives training, high-frequency communication, vehicle maintenance and a lot of medical training. In the jungle course, an officer hit his head on a rock and was evacuated. When we were being taught to blow up trees to make a helicopter landing space, a huge poisonous spider landed down the neck of the medical orderly, so he had to be evacuated too, and the radio operator got dengue fever.

"There was a lot of medical training. I remember fainting when they were showing slides about operating on an eyeball. It was such a macho atmosphere that five years later they were still taking the mickey out of me in the pub." By this time, he was no longer in the SAS, having been sent back to the Scots Greys after 18 months.

He was caught helping friends in a protest against 20th Century Fox, which, while making the Rex Harrison film of Dr Dolittle, was spoiling the pretty Cotswold village of Castle Combe. He attempted to blow up a newly built dam which was ruining a trout stream but someone tipped off the local bobbies. Unfortunately, this situation wasn't covered in the jungle training manuals.

To support Sir Ranulph Fiennes, go to www.mariecurie.org.uk/EigerChallenge or call 0800 716 146.

jonty@jonathansale.com