LONDON (AP) — Former British Treasury chief Geoffrey Howe, a longtime senior figure in the Conservative Party, has died at 88.

Howe died suddenly of a suspected heart attack late Friday at his home in Warwickshire, north of London, his family said Saturday.

Prime Minister David Cameron called Howe "the quiet hero of the first Thatcher government," praising him as a "kind, gentle and deeply thoughtful man" who nonetheless had "huge courage and resolve." He singled out Howe's action to lift exchange controls as a crucial move that helped save Britain's economy.

"(Howe) 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."

Howe was Thatcher's longest-serving Cabinet minister but also helped to end her time in office with a critical speech in 1990 as he was resigning from Parliament after a series of policy disagreements with the prime minister. They parted ways over policy toward Europe and other issues.

In a dramatic speech, Howe criticized Thatcher of undermining economic and monetary policies that had been supported by her Cabinet and the Bank of England chief. She resigned three weeks later after losing party backing.

His family said Howe died after enjoying a jazz concert with his wife Elspeth.