Movie studios must offer a broader range of films over the internet to prevent illegal downloading spreading into the mainstream, analysts have warned.

Forrester acknowledged in a newly published report that movie downloading is "still in its infancy". But of the five per cent of the online population who have downloaded a movie, more than one in three has downloaded three or more movies in the past three months.

"The profile of movie downloaders is similar to that of the early music downloaders, so it's time to ring the alarm bells," the analyst firm stated.

"Studios must accelerate a broader offering of digital rights management-protected movies for download to keep illegal movie downloading from spreading to the mainstream."

Forrester warned that developments in technology such as XviD and DivX formats, as well as the evolution of file-sharing tools such as BitTorrent, will further fuel movie downloading.

The film industry should respond to this new enthusiasm by targeting the P2P networks and providing consumers with legal alternatives, according to the analyst.

Hellen Omwando, consumer markets analyst at Forrester, said: "Currently, five per cent of online consumers in the UK have downloaded at least one full-length movie in the past three months.

"Their profile is similar to that of the early adopters who started sharing pirated music, which significantly reduced music sales. The spread of broadband is changing online behaviour."