In April 1940, despite being crippled by severe osteoarthritis, she hosted a conference at 11 Downing Street, where she emphasised the importance of preparing the people of the Empire for home rule and opposing racial discrimination. The same year, her husband was created Viscount Simon and she became Viscountess Simon. Lady Simon's husband died in 1954. She died at her home in Golders Green in 1955 and was cremated at Golders Green Crematorium.