LONDON — Former British finance minister Geoffrey Howe, an ally turned critic of Margaret Thatcher, has died at the age of 88, Prime Minister David Cameron’s office said Saturday.

Howe, who was also a former foreign secretary, died Friday after suffering a suspected heart attack, the BBC said, citing his family.

He oversaw Britain’s recovery from recession in the 1980s and was a champion of closer European unity — a belief which put him in direct confrontation with Thatcher and eventually became a catalyst for his exit from government.

Prime Minister David Cameron and Chancellor of the Exchequer George Osborne paid tribute to Howe, who served as finance minister from 1979 to 1983, on social media, emphasizing his quiet demeanor and radical thinking.

“His time as Chancellor of the Exchequer was vital in turning the fortunes of our country around, cutting borrowing, lowering tax rates and conquering inflation,” Cameron said.

“Lifting exchange controls may seem obvious now, but it was revolutionary back then.”

For 11 years, Howe was Thatcher’s loyal and self-effacing aide.

He was Chancellor during Thatcher’s first term as prime minister and administered the tough economic medicine that led to Britain’s mid-1980s revival from the worst recession in 50 years.

She rewarded his four-year Treasury stint by moving him to the Foreign Office in 1983, where he became Britain’s longest serving foreign minister since World War I.

He was a passionate proponent of joining Europe’s single currency, flying in the face of his increasingly euroskeptic Conservative party.

Thatcher also made him the government’s business manager in the House of Commons and her official deputy but 15 months later he quit the cabinet in a row over her resistance to closer European unity.

The outburst was a catalyst for Thatcher’s ousting by her own party only a few weeks later.

In a revenge attack in parliament, Howe booked his place in history and stunned MPs with a scathing attack on the “Iron Lady” and her comments on the hazards of European integration.

Howe described Thatcher’s increasingly jaundiced attitude to Europe as akin to “sending your opening batsmen to the crease only for them to find … that their bats have been broken before the game by the team captain.”

He is the second former statesman in a week to pass away after British Labour Party veteran Denis Healey died last Saturday aged 98.

Loyalty and restraint were his hallmark.

In their tributes on social media, Cameron described him as “the quiet hero” of Thatcher’s first government while Osborne said he was a “quietly-spoken radical.”

Some observers said his lack of aggression was a liability.

Labour’s Healey once described a rhetorical onslaught from Howe as akin to being “savaged by a dead sheep.”

He graduated in arts and law from Cambridge University, was married to Elspeth Morton Shand and leaves three children.

A bespectacled, portly figure, he was meticulous and always well prepared — as he demonstrated when his trousers were once stolen from his sleeping car on a overnight train journey.

He emerged with his dignity intact, explaining: “Luckily, I always carry a spare pair.”