Eternal Sunshine of the Spotless Mind actress Kate Winslet came third (16%), trailed by former Brookside actress Anna Friel (11%).
Hollywood queen Catherine Zeta-Jones, 34, came fifth (9%), followed by The Mummy star Rachel Weisz (6%).
Austin Powers actress Liz Hurley came seventh, followed by Helena Bonham Carter, Kristen Scott Thomas and Joely Richardson.
The survey was carried out by UCI Cinemas to mark the release of the Greek epic Troy, in which German actress Diane Kruger plays Helen of Troy, whose face was so beautiful that it "launched 1,000 ships".
Movie fans were asked which British actress was a 21st-century Helen.
UCI Cinemas' Lianne Butterfield said: "There are so many stunning British actresses, and a huge amount of talent. It's great to see so much home-grown talent starring in leading roles in this year's Hollywood releases."
UCI surveyed 1,005 people at cinemas in Cardiff, Manchester and Greenwich.