The 20-year-old Harry Potter actress also put Victoria Beckham in the shade, with the singer-turned-fashion designer coming second, followed by Keira Knightley, Cheryl Cole and Sienna Miller.
Supermodel Moss was sixth, with Lily Allen, Pixie Lott, Naomi Campbell and Lungs singer Florence Welch completing the top 10.
Twilight star Robert Pattinson, 24, was named Britain's best-dressed man, with Scottish actor Gerard Butler in second place.
David Beckham was fifth, followed by Orlando Bloom, Gossip Girl's Ed Westwick, chart-toppers JLS, Jude Law and Ewan McGregor.
Around 25,000 people voted in the Glamour.Com Best Dressed Brits List.
