Lady Soames, the last surviving child of Sir Winston Churchill, has died.
Mary Soames, who was 91, died peacefully at home in west London yesterday evening surrounded by her family, after a short illness.
She was the youngest of the five children of the wartime prime minister and his wife Clementine.
One of her sons, the Conservative MP Nicholas Soames, said: "She was a truly remarkable and extraordinary woman, who led a very distinguished life."
Mary Churchill worked for the Red Cross and the Women's Voluntary Service from 1939 to 1941, and joined the Auxiliary Territorial Service with whom she served in London, Belgium and Germany in mixed anti-aircraft batteries, rising to the rank of Junior Commander (equivalent to Captain).
She also accompanied her father as aide-de-camp on several of his overseas journeys, including his post-VE trip to Potsdam, where he met with US president Harry S Truman and Soviet leader Joseph Stalin.
She married the Conservative politician Christopher Soames (later Baron Soames) in 1947 and they had five children - Nicholas, Emma, Jeremy, Charlotte and Rupert.
Lady Soames served many public organisations, such as the International Churchill Society, as a Patron; Church Army and Churchill Houses; and chaired the Royal National Theatre. She was Patron of the National Benevolent Fund for the Aged.
She was made a Dame Commander of the Order of the British Empire for her public service, particularly in Rhodesia, now Zimbabwe, and was appointed a Lady Companion of the Order of the Garter in 2005.
She wrote an acclaimed biography of her mother, Clementine Churchill, in 1979, which won a Wolfson Prize, and her own memoirs.
Mr Soames said: "She was not just a wonderful mother to whom we were all devoted, but the head and heart of our family after our father died, and will be greatly missed.
"She was a distinguished writer and led a distinguished life, with her service in the War, and is part of that generation which is passing. This is extraordinary timing - just before the anniversary of the Normandy landings, Churchill's last surviving child dies. It is the great swing of history."
Prime Minister David Cameron said: "I am saddened to hear that Mary Soames, Winston Churchill's last surviving child, has died. She was a wonderful, warm hearted woman who could always put others at ease. She was very kind to Samantha and me and we felt privileged to know her.
"In the week of the 70th anniversary of D-Day, we remember that she served her country in World War II and was an eye-witness to some of the most important moments in our recent history as she accompanied her father to key conferences.
"My thoughts are with her family, who can take pride in her distinguished life."