Lewin of Greenwich: The Authorised Biography of Admiral of the Fleet Lord Lewin
Richard Hill
443pp, Casell
£25
Buy it at a discount at BOL

Naval biography in this country has a long and distinguished history, naval autobiography less so. In the tradition of "the Silent Service", as the Royal Navy is sometimes known, most admirals have preferred to leave their memoirs to others. There have been many biographies of Nelson, of course, and John Winton wrote perhaps the classic of the genre in his biography of Admiral Cunningham. This included the hilarious detail that anti-submarine tactics of the first world war were initially limited to sending out a rowing boat containing the ship's blacksmith, a large hammer and several sacks. If the blacksmith were unsuccessful in smashing the protruding periscope with the hammer, a sack was placed over it, thus blinding the submarine.

Of biographies of postwar admirals, including Mountbatten, none has covered the career of an officer who was more important or influential in the development of the post-colonial Royal Navy than Admiral of the Fleet Lord Lewin. Chief of the defence staff during the Falklands conflict, in the course of his 40-year career he watched the Royal Navy shrink from the largest and arguably the most powerful navy in the world to almost its present size. He saw the introduction of radar, the replacement of the battleship by the aircraft carrier, and the introduction of nuclear-powered submarines (Polaris and Trident). He witnessed the Sandys and Nott defence reviews, which severely diminished the role of the Navy, and the cancellation of the Royal Navy's aircraft-carrier programme under Denis Healey in the 1960s.

Richard Hill, himself a retired rear admiral, writes knowledgably and consistently about Lewin - at, it should be said, his subject's invitation. They served together on several occasions, and Hill interviewed 150 people in the course of his research. His most important source was Lewin himself, who while dying of cancer dictated more than 50,000 words for the benefit of his biographer.

Born in 1920, Terence Thornton Lewin had the typical background for an officer in the Royal Navy: he did not come from a wealthy background (Nelson was the son of a Norfolk vicar), had no family connection with the Navy and did not attend a public school. Unusually - at a time when most putative naval officers joined Britannia Royal Naval College in Dartmouth at 13 - Lewin was a Special Entry cadet, joining at the last possible opportunity at the age of 18, having failed to get into university. Although promotion in the Navy has been based at least partly on merit since the time of Pepys, the Special Entry officers were viewed with some suspicion by those who joined by the traditional route, and relatively few were expected to reach the highest ranks.

Lewin's training was cut short by the outbreak of war: after HMS Belfast (preserved today at Tower Bridge) was badly damaged by a new "secret" weapon, the magnetic mine, he was posted to the battleship HMS Valiant, which had just undergone a major refit, including the fitting of one of the first radar sets. His time in Valiant included the shelling of the French Fleet at Mers-el-Kebir and the attack on Taranto, which was the model for the Japanese attack on Pearl Harbor. He spent much of the rest of the war on the Arctic convoys and afterwards specialised in gunnery, commanded a frigate, served as second in command of the Royal Yacht, and worked in frigate design at the Admiralty.

Much of the remainder of the story concerns Lewin's role in the reconsideration of British naval power that came with the retreat from empire. This is why he is important: for the first time since the defeat of the Armada, national identity would cease to be associated with that old and increasingly expensive tune, "Britannia rules the waves".

Lewin saw it all. In 1964 he was again appointed to the Admiralty, which under Mountbatten was being merged with the Air Ministry and the War Office to form the combined Ministry of Defence. The Labour victory of that year bought about an immediate major defence review under Denis Healey. A bitter argument between the Navy and the RAF led to the cancellation of the Navy's new aircraft carriers and their planned (later cancelled) replacement with RAF jets flying from land bases.

Within a few years, and with Lewin's involvement, the Royal Navy was tentatively working towards procuring the Sea Harrier, to operate from what were being euphemistically called "through deck cruisers". It is even said that the politicians were carefully shown only side views of the ship, so that they wouldn't realise that they were actually ordering a smallish aircraft carrier. If such arguments had not eventually succeeded, the Falklands task force would have been impossible.

Lewin became First Sea Lord - the professional head of the Navy - in 1977. From this lofty viewpoint he was able to witness the success of some of his earlier work, such as the launching of the first of the new aircraft carriers (HMS Invincible) and a fly-past of the new Sea Harrier.

But the Navy's troubles were far from over. In September 1979, under a newly elected Margaret Thatcher, the decision to purchase Trident was taken. However, the service would have to pay for it out of its own budget. Defence Secretary John Nott's associated review of naval resources caused trauma throughout the fleet. Invincible was to be sold to Australia; the specialised landing ships Fearless and Intrepid were to be scrapped; the South Atlantic patrol ship HMS Endurance was to be withdrawn. It seemed, if things went on like this, that the Royal Navy would be reduced to nothing but a "coast defence force". One government minister, Keith Speed, resigned on principle against the cuts. Lewin did not resign, probably reasoning that it would only make matters worse, but he must have been bitterly disappointed.

Then came the Falklands conflict, in which many of the remaining resources were put to the test. Thatcher was told that a task force not only could, but should, respond to the Argentine invasion. Lewin himself never doubted the decision to sink the General Belgrano, though he regretted the heavy loss of life. It is now generally felt by the Navy that this was unnecessarily heavy, but that the blame must be placed on the Argentinian response to the attack.

Lewin retired in October 1982, and died 17 years later. He wanted to be remembered for bringing about social change, making the Navy "more egalitarian and family-conscious" without losing "its traditions and heritage". He was not against women at sea, but was concerned about his experiences of homosexuality at sea and its link to indiscipline. His wider legacy - at least as perceived in this readable and comprehensive, if not exactly exciting, biography - is that of an officer whose battles were more often with the civil service, politicians and on occasion other services than with the enemy fleet. But they were necessary battles and ones he fought bravely. No one was more closely involved in bringing the Royal Navy into the modern era.