John Adams was a man of remarkable ability, intellect and charm. His final tour as Assistant Chief of Naval Staff (Policy) in the Ministry of Defence (MoD) had a fundamental influence on the future shape and size of the fleet during a period of acute financial stress, both nationally and in respect of the naval budget.

The Admiralty Board had always argued that Britain’s east-of-Suez posture required a capable aircraft carrier force — in the 1950s Britain’s contribution to the UN during the several years of the Korean War had included a permanent carrier presence. Thus the decision in February 1966 to abandon on cost grounds the future large carrier, known as “CVA01”, was the most traumatic shock to the Royal Navy of the whole postwar period — all of naval experience during and after the Second World War had demonstrated the necessity of fixed-wing naval aviation to a balanced fleet.

The First Sea Lord, Admiral Sir David Luce, and the Minister of Defence (Royal Navy), Christopher Mayhew, resigned over the Government’s decision. Succeeding Luce, Admiral Sir Varyl Begg had the task of picking up by the bootstraps a Navy now in poor shape and putting the show back on the road.

He selected Adams to head a Future Fleet Working Party in April 1966, directing him to report within six months with an overall plan for a Navy without carriers. As the Foreign Office could produce no statement of the future shape of British interests, the working party had to make its own assessments.

Given the need for flexibility and the possibility of operating far from shore, Adams saw no alternative to a big command ship with helicopters and vertical take-off (VSTOL) aircraft, however simply constructed. A vessel of this nature was the kernel of an immense amount of work covering all aspects of naval capability and support. But an implacable First Sea Lord, refusing to reopen the “carrier question”, was furious and shelved the report, deciding that it should not be presented to the Admiralty Board for implementation. Adams was told that he was not to be recommended for further employment, a departure seen as a considerable loss to the service.

Yet the working party’s talented staff officers over the next decade rose to positions of influence, some at board level, and were able to nudge its conclusions towards a blueprint for a Navy, after the withdrawal from east of Suez in 1968, that was firmly based on a Nato role with the capability to act further afield. MoD insiders say that Adams was subsequently further vindicated by a paper by Commander John David, “The Missile Gap”, that described how Soviet long-range reconnaissance aircraft would soon be able to target defenceless Allied surface ships by data link to Soviet missiles. The solution was further support for Adams’s euphemistic “through-deck cruisers”, the Invincible Class carriers with their Harrier VSTOL fighters, so effective in 1982 against the Argentine Air Force.

John Adams joined the Navy in 1936. At the outbreak of war he was a sub-lieutenant in the destroyer Walker, which supported attacks on Narvik and evacuated British troops from Norway. After he left the ship she was, in March 1941, part of Commander Donald McIntyre’s celebrated 5th Escort Group during the defence of Convoy HX112 with the destroyer Vanoc, which sank U99 and captured the U-boat ace Lt-Cdr Otto Kretschmer. In June 1941 Adams was posted to the Hunt-Class destroyer Cleveland as second-in-command, providing support for the celebrated March 1942 attack by the destroyer Campbeltown on the St Nazaire dock gates in Brittany. In September 1942 he was mentioned in dispatches for an action against E-boats in the Channel. Cleveland took part in the Allied landings in North Africa and then the invasion of Sicily.

Adams qualified as a torpedo expert in June 1943, joining the staff of the Captain (Destroyers) Western Approaches in January 1944. After the war he became an anti-submarine specialist, a qualification that coloured much of his career. After commanding the destroyer Creole, he worked for the Flag Officer Submarines and with the Naval staff in the anti-submarine division.

In 1954 his high professional standards were recognised by appointment to the newly commissioned Royal Yacht Britannia as the first executive officer. Among the royal cruises during his tour was one to the Antarctic. He was appointed MVO (later LVO).

Although not a submariner, he was selected most unusually to be captain of the 3rd Submarine Squadron and the depot ship Adamant. A contemporary submarine CO reported: “Captain (SM) came on board and knew more about my submarine than I did.”

It was widely believed that but for his difficulties with Begg he would have made an excellent Flag Officer Submarines, there having been previous non-submariner precedents.

From 1960 to 1962 he was captain superintendent of the Admiralty Underwater Weapons Establishment at Portland, Dorset. In early 1961 he was somewhat taken aback when two inconspicuous gentlemen appeared in his office and said: “Sir, you have a Soviet spy in your establishment.” Thus began the famous Portland spy case that resulted in Ethel Gee and Henry Houghton, both Portland civil servants, Gordon Lonsdale, and Peter and Helen Kroger, Soviet agents, being convicted of spying and imprisoned.

Adams recalled being persuaded against his better judgment to allow Gee to make off with details of Britain’s first nuclear submarine Dreadnought’s Type 2001 bow sonar array; this bait assuring her arrest. Many years later the family that took over the Krogers’ Weymouth house found another high-powered radio set buried in the garden.

After the 1963 mind-stretching course at the Imperial Defence College in Belgrave Square, Adams was given command of the commando carrier Albion from May 1964 to 1966. Operating between Aden, Singapore, Borneo and Sarawak, Albion and her Wessex helicopters played an important part in the protracted Indonesian “confrontation” campaign as British, Gurkha and Australian forces prevented the disruption of the new-born state of Malaysia by President Sukarno of Indonesia. Adams amassed more than 100 hours flying in helicopters.

He was appointed CB on leaving the Navy, becoming director of the new Paper and Paper Products Industry Training Board, subsequently director of the employers’ federation and finally director-general of the British Paper and Board trade association.

From 1983 he ran his own business, DUO (UK), a small management consultancy helping executives to make presentations to government, the European Community and the media, also guiding sixth-formers and other young people towards university and job interviews. He also worked for divisions of the European Commission.

His wife, Ione, died in 1998. They had two sons and two daughters.

Rear-Admiral John Adams, CB, LVO, Assistant Chief of Naval Staff (Policy) 1966-68, was born on December 19, 1918. He died on November 3, 2008, aged 89