LADY Soames, who has died aged 91, was the last surviving child of Sir Winston and Clementine Churchill who, unlike her siblings, enjoyed a long and fulfilled life beyond the long shadow cast by her father.
Mary Soames was born in London during a low point in her father's career after he lost his Dundee seat and before he rejoined the Conservatives in 1925.
In the year she was born Sir Winston bought Chartwell, his country home in Kent, and young Mary was educated nearby.
She left school aged 17 and, during the first two years of the war, served with the Red Cross and the Women's Voluntary Service (WVS) before joining the Auxiliary Territorial Service (ATS) and serving in mixed anti-aircraft batteries, rising to the rank equivalent to captain.
She relished her time in the ATS, which also included time serving in Hamburg at the end of the war. She recalled: "Uniform is a tremendous leveller. We all looked the same, lovely girls from Liverpool and country bumpkins like me. If you were an officer, you were a real part of the gun team, not just in charge of the girls' shoes and ticking them off."
She was eight years younger than her nearest sister, Sarah, and was brought up rather like an only child.
Her father would often visit during air raids and she acted as aide-de-camp to him on several overseas trips, including the first Quebec conference in August 1943 between Churchill, Roosevelt and the Canadian Prime Minister Mackenzie King.
She also joined him at Potsdam for the conference in the summer of 1945 and helped to arrange his dinner with Stalin - whom she remembered as "small, dapper and rather twinkly". The conference concluded after Sir Winston had been defeated by Labour in the general election.
She was demobilised in 1946 and appointed MBE (military). While she and her father had been staying at the British Embassy in Paris she met Capt Christopher Soames of the Coldstream Guards, who was then the assistant military attaché. They married in 1947 in St Margaret's, Westminster, the same church as her parents.
She was a dogged supporter of her husband's political career as a Conservative MP for Bedford (1950-66) and after he lost his seat, she accompanied him on a series of foreign appointments, which included his time as British ambassador in Paris between 1968-72.
During her four years in Paris she knew not only presidents de Gaulle and Pompidou but also the Duke and Duchess of Windsor.
The couple were in Brussels from 1973 to 1976, when her husband (who became Lord Soames in 1978) was the first British vice-president of the European commission. Between December 1979 and April 1980 he was the last governor of Southern Rhodesia and oversaw the delicate transfer of power. Lady Soames was aggrieved by the subsequent fate of Zimbabwe under the rule of Robert Mugabe.
While in Brussels she began working on her mother's life story. Despite having "never before written so much as a pamphlet" Clementine Churchill (1979) was a success, winning the Wolfson Prize. Other books followed, including Winston Churchill: His Life as a Painter (1990) and a collection of her parents' letters, Speaking for Themselves (1998). An autobiography up to 1945, A Daughter's Tale (2011), drew on her extensive diaries.
Lord Soames died in 1987 and two years later she was unexpectedly appointed chairwoman of the Royal National Theatre Board.
On her arrival she admitted to the new director Richard Eyre: "I haven't been to the theatre for years. Treat me as if I know nothing."
But she proved a success, brought in sponsorship and was re-elected for a second three-year term just before her 70th birthday.
Her brother's and sisters' lives were not so blessed. Diana committed suicide in 1963, Sarah and Randolph both died young (in 1968 and 1982).
In 2005 she was appointed Lady Companion of the Order of the Garter and is survived her five children, Nicholas, Emma, Jeremy, Charlotte and Rupert, a businessman and former chief executive of the Glasgow power firm Aggreko.