Will Smith plays the last man on Earth in I Am Legend

The film, about the global population being wiped out by a virus, has so far taken a total of �18.5m.

Romantic drama PS I Love You follows in second place, with fantasy drama Enchanted entering at number three.

Spoof comedy St Trinian's, starring Colin Firth, appears in fourth place while Daniel Craig's The Golden Compass rounds off the top five.

UK AND IRELAND BOX OFFICE 1. I Am Legend - �3.7m 2. PS I Love You - �1.7m 3. Enchanted - �1.4m 4. St Trinian's - �1.37m 5. The Golden Compass - �1.32m 4-6 January. Source: Screen International

Alvin and the Chipmunks fell from last week's fifth place to sixth, and Bee Movie also fell a place to number seven.

In eighth place was The Kite Runner, followed by comedy Balls of Fury.