Lord Cuckney: Former MI5 officer who became a political and financial fixer for both Tory and Labour governments

John Graham Cuckney spent time in the army and as an officer in MI5, but the long years he spent in industry and the commercial world, tackling the very thorniest problems, were the hallmark of his career. As one of the ultimate high-level fixers, he was called onby Labour and Conservative administrations to deal with issues involving huge amounts of both money and political credibility.

One of these, the Westland helicopter affair, looked at one stage as though it could topple the Thatcher government. Although it didn't, it was a messy business; but when the smoke cleared, Cuckney characteristically emerged unscathed. His proficiency at managing crises made him invaluable to whichever government was in power, and ensured that an unending stream of financially and politically complex problems were dumped in his in-tray. He seemed to relish them all.

Cuckney, who was to become first a knight and later a lord, was born in 1925 in India, the son of the much-decorated Air Vice-Marshal E. J. Cuckney, who had been a First World War pilot. He attended Shrewsbury School before studying medicine at St Andrews. His university life was interrupted by the Second World War, in which he served with the Royal Northumberland Fusiliers and the King's African Rifles.

On his return to St Andrews, he gave up his ambition to become a surgeon and switched to economics and history. He later went on to join MI5, in a role coyly described in Who's Who as "War Office, civil assistant, general staff". His involvement in the world of espionage, which lasted around a decade, only came to light about 30 years after he had left MI5. He was outed when the MI5 "whistleblower" Peter Wright named him in his 1987 autobiography, Spycatcher. Wright said that when Cuckney had lectured him on joining MI5, he had stressed the doctrine of "thou shalt not get caught". He also recalled that during his training, Cuckney had said of MI5's legal status: "It hasn't got one. The Security Service cannot have the normal status of a Whitehall department because its work very often involves transgressing propriety or the law."

Cuckney dressed in bolder styles than the standard MI5 dark pinstripe, Wright reported, describing his personal style as tough and no-nonsense and remembering that he could be "downright rude". It is not known what else Cuckney did while in MI5, but by the time Wright blew his cover he had left the world of espionage for that of commerce and high finance. His business career sometimes involved him with military and intelligence concerns, so his background was of continuing value to him.

By the late 1950s he had plunged into the City, prospering within the Pearson empire, before moving into banking and trade with the Middle East. The years that followed led him into innumerable boardrooms as he established himself as one of the business world's natural chairmen. He was variously described as tall, imposing and courteous. His business interests included, at various times, major concerns such as the Midland Bank, Royal Insurance and many more.

Both Labour and the Tories liked Cuckney's style, and on many occasions he was drafted into the public sector, at times to steer going concerns and at others to mount rescue missions. Labour commissioned him to set the ailing Mersey Docks to rights, and put him in charge of the Property Services Agency and the Crown Agents. He was also placed at the head of a Ministry of Defence company. In most cases he was judged a success, partly because of his dispassionate way with ventures which were not working. He was called a "company doctor", but was known to be a ruthless operator with concerns that he believed were too weak to survive.

Cuckney was involved in controversial projects such as Matrix Churchill and Pergau Dam, but the most controversial of all was the Westland Helicopter affair in the mid-1980s. Cuckney was chairman of Westland, having been sent in to save a company which was close to bankruptcy. Much debate went on within Margaret Thatcher's cabinet, with Thatcher and her Defence Secretary, Michael Heseltine, locked in a heated argument. She, like Cuckney, favoured a tie-in with an American company; Heseltine favoured a European consortium. Cuckney found himself in the midst of a controversy in which two of the biggest beasts of the political jungle circled each other, on the point of combat.

In some ways it was a perfect storm, since it involved not just commercial interests but deep-seated issues of whether Britain should be orientated towards the US or Europe, and indeed who should be prime minister. It was exactly the sort of crisis he was suited to handle, and the Thatcher-Cuckney line prevailed. Heseltine, of course, resigned from the cabinet and later challenged Thatcher for the leadership of the Tory party, unsuccessfully.

Cuckney's reputation for cool judgment was much enhanced by the affair. Not long afterwards, however, he headed a consortium which unsuccessfully bid to take over the giant firm GEC. This slightly dented his reputation as a courtly captain of industry, and he found himself described as something of a corporate buccaneer.

His credit ratings rose again in the early 1990s, however, when he took on the apparently thankless task of finding and administering some of the hundreds of millions which the crooked media tycoon Robert Maxwell had filched from pension funds. He recovered a substantial amount of the money and helped to broker a multi-million pound settlement.

He received a knighthood from Labour and a peerage from the Conservatives.

David McKittrick

John Graham Cuckney, financier and industrialist: born India 12 July 1925; chairman, Mersey Docks and Harbour Board 1970-72; chief executive, Property Services Agency, Department of Environment 1972-74; chairman, International Military Services, Ministry of Defence 1974-85; Senior Crown agent and chairman for Overseas Governments and Administrations 1974-78; chairman, Economic Development Committee for Building 1976-80; chairman, Thomas Cook 1978-87; Kt 1978; chairman, Brooke Bond 1981-84; chairman, John Brown 1983-86; chairman, Westland 1985-89; chairman, Royal Insurance Holdings 1985-94; chairman, Investors in Industry (3i) 1987-92; chairman, Understanding Industry Trust 1988-91; chairman, Orion Publishing 1994-97; created 1995 Baron Cuckney of Millbank; married three times; died 30 October 2008.