The UK’s top civil servant, Sir Jeremy Heywood, has been receiving treatment for cancer.
The Cabinet Office said Sir Jeremy, who has been cabinet secretary since 2012, was diagnosed earlier this year.
In a statement, it said the 55-year old had received treatment over the summer and the early autumn which “went well”.
Sir Jeremy, it added, had continued his “normal duties” during this period with the full support of his doctors and remained “totally focused” on doing so.
As cabinet secretary and head of the civil service, Sir Jeremy is responsible for advising the prime minister and cabinet on the business of government.
The Cabinet Office said it would be making no further comment on “this private matter”.