Born in 1932, he attended Kings Mead, Steaford, Bradfield College and Trinity College, Cambridge.

He also served as a lieutenant in the Gurkha Rifles, fighting in the Malayan Emergency, a communist-inspired revolt against British colonial authorities.

In the 1966 election he won St Ives for the National Liberals, a party which merged with the Conservatives two years later.

He slowly rose through the parliamentary ranks and in 1981 Margaret Thatcher appointed him Defense Secretary.

After more than a year in office, he and the rest of the British government were largely surprised when the Falkland Islands were attacked by Argentina, which claims the territory as its own.

Sir John faced heavy criticism in the House of Commons for failing to foresee the attack and leaving the islands vulnerable to invasion.

Already bruised by rows over defense spending cuts the previous year, he pleaded with Thatcher to be allowed to resign.

If she accepted the resignation of Lord Carrington, then Minister of Foreign Affairs, she refused to let Sir John go, saying “she could not accept it” while the British task force was still carrying out its operation to take over the islands.

Initially, Sir John was skeptical that the United Kingdom could regain the territory. However, his doubts were quickly dispelled and he later hailed the deployment as “a remarkable achievement”.

Speaking to the BBC in 2002, he dismissed criticism of the infamous sinking of the Argentine ship, the Belgrano, in which 323 sailors died.

“We didn’t start the war. There was a big army of people trying to blame us for the war. (But) we were negotiating peacefully with the Argentines,” he said.

“It was a terrible tragedy. I was shocked when all those Argentine soldiers died. It was really terrible.”

However, he said that after the incident, the Argentine Navy never went to sea, adding: “If we had to fight not only against the very brave Argentine pilots, but also against the Argentine Navy, it would have been much more difficult.”

After the British victory in June 1982, Sir John again requested to be allowed to resign and was finally granted his request in 1983.