Leon Brittan, who was a European commissioner for ten years and a leading figure in the development of the World Trade Organisation, has died at the age of 75. He had been suffering from cancer.

When Jacques Delors was president of the European Commission, Brittan was the only commissioner who came close to rivalling his influence. After Delors had been succeeded by Jacques Santer, Brittan was the dominant intellectual force in the college of commissioners.

Jean-Claude Juncker, the current president of the European Commission, led the tributes to someone he described as “a true European”, who had “demonstrated his total mastery of complex issues and was a strong advocate for the single market”.

Brittan’s appointment as a European commissioner came after a career in British government that was distinguished, though marred by a succession of controversies.

Elected to the national parliament in 1974, Brittan was swiftly promoted by Margaret Thatcher, who assumed leadership of the Conservative Party in 1975 and became prime minister in 1979. Brittan was appointed to the cabinet in January 1981 as chief secretary to the treasury. He played an important role assisting the then finance minister Geoffrey Howe in imposing budgetary discipline. He was promoted to home secretary (interior minister) in 1983, but was dogged by presentational difficulties, particularly over policing and countering Northern Ireland terrorism.

Demoted to the position of industry minister in 1985, he retained a place in the cabinet until his ministerial career was abruptly ended by a bitter battle between Thatcher and her rival Michael Heseltine. Heseltine challenged Thatcher over the sale of Westland, a helicopter company, seeking to block its sale to Sikorski, an American company, in favour of a European consortium. Brittan was obliged to resign when it emerged that his office had leaked information against Heseltine. Observers at the time thought that Brittan was sacrificed to save Thatcher.

Brittan’s nomination to the European Commission three years later came as some kind of compensation for having taken the heat for Thatcher, though he was initially reluctant to relinquish his parliamentary seat. Ironically, in view of how he had been cast in an anti-European role by Heseltine during the Westland affair, he proved a doughty champion of European interests. The younger son of Lithuanian Jewish immigrants, and born in the first month of the Second World War, he was emotionally as well as intellectually European in his perspective.

It was the intellect that dominated in his years as European commissioner for competition in 1989-93, when the tough line that he took on state aid cases brought him into frequent conflict with Delors, a French socialist. Charles Grant, now head of the Centre for European Reform, a think-tank in London, witnessed the contests between Delors and Brittan as a correspondent for The Economist in Brussels. He said that Brittan had, following in the footsteps of his predecessor Peter Sutherland, established and made permanent European competition policy.

From 1993 until he left Brussels in 1999 at the end of the Santer Commission, Brittan was European commissioner for trade. He acquired additional responsibilities for external relations (with some parts of the world) from 1995.  It was a crucial period in the development of the governance of world trade. The General Agreement on Tariffs and Trade was revised in 1993, leading to the establishment of the World Trade Organisation from the beginning of 1995. Brittan was a high-profile protagonist in some of the leading trade disputes at the time, notably with the US over bananas and hormone-treated beef. But he also sought to advance bilateral trade relations with the US, proposing an early form of transatlantic partnership agreement.

Whereas his political career in the UK was constrained by a debating manner that was ill-suited to the television era, his lawyerly, technocratic demeanour was well-suited to the work of a commissioner in Brussels, where political grandstanding – at least in those days – was always dependent on the primary task of mastering the brief. In this respect, his capacity for hard work put him far ahead of a potential intellectual rival in the Santer Commission, the clever but lazy Martin Bangemann.

It helped too that Brittan was accomplished in spotting talent and recruiting talent to his private office. Those who passed through the Brittan cabinet included Catherine Day, who is now secretary-general of the Commission, Jonathan Faull, the director-general for financial stability, financial services and capital markets union, Robert Madelin, the director-general for communications networks, content and technology, Joost Korte, deputy director-general for agriculture and rural development, Ivan Rogers, the UK’s permanent representative to the EU, Simon Fraser, now the most senior civil servant at the UK’s foreign ministry, and Nick Clegg, the UK’s deputy prime minister.