I've been re-reading John Colville's "The Fringes Of Power".
It's the diary of Churchill's private secretary during the war. He was at Chartwell on the June night in 1941 when Churchill, Eden, Beaverbrook and Roosevelt's envoy were staying there.
The following morning he was woken by a telegram informing him that Hitler had invaded Russia. What that meant was that Britain was going to get away with it. It was probably the most significant piece of news for this country in the 20th century.
He went from bedroom to bedroom passing on the news.
He was twenty-five years old.