There was some further contact during the war, by virtue of the circles in which she and Eden both moved and through her uncle Winston, who became Prime Minister in May 1940. As an illustration of her occasional proximity to the centre of power, between meetings of the War Cabinet on 30 May 1940, when the Dunkirk evacuation was at its height, Clarissa was present when Churchill lunched with her parents and the Duke and Duchess of Marlborough. Lady Avon has described this occasion as "a nightmare, with news of people's deaths coming in …". After her mother's death in 1941, she stayed at Chequers, the Prime Minister's country home in Buckinghamshire.