James’s health declined after the Second World War and, being childless, he needed to plan for the future of Waddesdon. He decided to leave the house, most of the important collections and the grounds around the house to the National Trust. A management committee was established, to be chaired by a family member and a large endowment ensured the family’s continued financing of the operations.
For nearly 30 years, Dorothy chaired the committee and oversaw the opening of the house to the public.
At her death in 1988, she left the responsibility for Waddesdon to Jacob, Lord Rothschild (b. 1936), already a leading figure in the world of art and culture. A successful financier who had left the family bank to establish his own financial business, he was deeply interested in heritage and the arts. He chaired the boards of the National Gallery and the National Heritage Lottery Fund. He restored Spencer House in London and masterminded the five-year restoration of Waddesdon from 1990 to 1995. His significant contributions have been recognized with the award of the Order of Merit in 2002.
Under his leadership, the Rothschild Foundation now manages Waddesdon on behalf of the National Trust, and has continued to add to the collections, with both 18th-century and contemporary art. He also has the Rothschild gene for building and oversaw the complete restoration of the Dairy, the creation of the Coach House Gallery at the Stables, and the construction of the Windmill Hill complex and the Flint House.