Welsh star Catherine, 41, beat Geordie star Cheryl Cole, 28, and Kelly Brook, 31, to the title.
Hollywood legend Elizabeth Taylor came second in the survey, followed by Princess Diana in third place.
An analysis of the top 100 most beautiful British women of all time shows that the most beautiful women are an average height of 5ft 5in, have brown hair, blue eyes, and are actresses.
The poll, of 2,000 men and women viewers, was carried out by shopping channel QVC to mark its beauty month.
Actresses Keira Knightley, 26, and Kate Beckinsale, 37, also feature in the top 10.