Sir Ranulph Fiennes has become the oldest Briton and the first British pensioner to reach the summit of Everest. It was the 65-year-old's third attempt at conquering the 8,850m Himalayan giant. During his 2005 attempt, Sir Ranulph had a heart attack at 8,500m and last year he was forced to turn back at 8,400m after suffering from exhaustion. On his arriving at the summit, the veteran explorer became the first man to cross the north and south poles and climb the world's highest peak. The record-breaking adventurer, who hopes to raise £3 million for cancer charity Marie Curie, had a triple heart bypass in 2003 following a heart attack. Sir Ranulph said: "I have summited Everest for Marie Curie Cancer Care which has long been a personal goal. "Thanks to my sponsor Brewin Dolphin for making this possible. I urge everyone who followed my attempt last year to give generously to Marie Curie so that we can at last achieve our £3 million target to support its pioneering work in end-of-life care." Sir Ranulph apparently began his latest assault on Everest three weeks ago, but chose to keep the expedition low-key after his two unsuccessful attempts. A spokeswoman for Marie Curie said: "He wanted to do it quietly with no fuss. He only just failed last year - he got to within a short distance of the summit but had to turn back from exhaustion. "So he decided he wanted to keep it very low-key without all the build-up and media attention of last year." After his second attempt Sir Ranulph said: "I won't be returning to Everest. It's a seven week trip - last time I had a heart attack, this time bad timing and weather scuppered my chances. I think any third attempt would be bad luck." Among Sir Ranulph's numerous achievements are becoming the first man to reach the north and south poles by land unaided, completing seven marathons on seven continents in seven days in 2003 and climbing the treacherous north face of the Eiger in 2007. Sir Ranulph also joined solo yachtsman Sir Robin Knox-Johnston and John Simpson, the BBC's world affairs editor, for the BBC Two series Top Dogs which saw the trio file war reports from Afghanistan, trek across the Arctic and sail around Cape Horn. Simpson said he was thrilled and extremely proud of his "close friend". He said: "I want to express my sheer delight and pride in his fantastic achievement I knew he would do it on the third attempt. We have already broken out the Champagne. "My son is named after him and this morning we will put a tiny drop in his milk so he can celebrate too." Sir Ranulph, who has already raised millions for Marie Curie Cancer Care, lost his first wife, sister and mother to cancer within 18 months.