The Welsh group were named 'Best British Band' for the third year running, as well as 'Best Live Band'.
Biffy Clyro, who hail from Scotland, won 'Best Video' for 'The Captain', and London-based Rise To Remain were awarded 'Best British Newcomers'.
Lostprophets won the 'Classic Songwriter' prize. American band 30 Seconds To Mars were named 'Best International Band'.
The ceremony took place last night.