"[citation needed] Cockfield left Boots to become an adviser to the Conservative politician Iain Macleod on taxation and economic matters, and was president of the Royal Statistical Society from 1968 to 1969.

In this role he had no specific departmental responsibilities, so he effectively became an advisor and a sort of one-man think-tank to the Prime Minister.

He was expected to follow Thatcher's eurosceptic line, but became a driving force in laying the groundwork for the creation of the Single European Market in 1992.

Only a few months after he arrived in Brussels, he produced a mammoth white paper listing 300 barriers to trade, with a timetable for them to be abolished.

[citation needed] After leaving the Commission in 1988, Cockfield became a consultant for accountants Peat, Marwick, McLintock.

He was awarded the Grand Cross of the Order of Leopold II of Belgium in 1990, and honorary doctorates and fellowships from a number of British and American universities.