Allen voiced her support for the singer, who has been nominated for her 2009 self-titled debut, on her Twitter page.

“I hope La Roux wins,” Allen wrote in a short message on the micro-blogging website.

Allen was a surprise omission from this year's shortlist having been strongly backed by fans and critics.

Other big names, including Oasis and Doves, also failed to pick up a nomination.

Kasabian, The Horrors and Bat For Lashes are among the twelve acts in contention for this year's Mercury Prize.

The prestigious award will be handed out at a ceremony in London on September 8.

(by Jason Gregory)