The British government says Jeremy Heywood, who ran the country's civil service until illness forced him to step down, has died of cancer. He was 56.

British Prime Minister Theresa May said Heywood, who died early Sunday, "worked tirelessly to serve our country" She called his death "a huge loss to British public life."

Jeremy Heywood, Who Ran Britain's Civil Service, Dies at 56

As Cabinet secretary, Heywood oversaw Britain's government bureaucracy. That made him a powerful figure, though little known outside the Whitehall government district.

Jeremy Heywood, Who Ran Britain's Civil Service, Dies at 56

Liberal Democrat leader Vince Cable said Heywood had advised politicians of right and left, and "none of us had the faintest idea what his politics were. He was just the perfect civil servant."

Jeremy Heywood, Who Ran Britain's Civil Service, Dies at 56

The government announced Oct. 24 that Heywood was retiring to fight his illness and granted him the title Lord Heywood of Whitehall.