Entries are now being accepted for this year's Serco Prize for Illustration, which is looking for artworks on a theme of 'secret London'.

The Prize is run by the London Transport Museum, in partnership with the Association of Illustrators (AoI). The winning entry will appear on Transport for London services as a poster, with the first prize winner also getting £2,000. The second prize is £1,000 and the third prize is £750.

Entrants are asked to create an illustration that explores a hidden side to the city. Entries can depict little known or unusual aspects of the Capital’s history, culture, characters and communities – past or present.

The organisers say that this is an exciting challenge for artists to celebrate a vibrant, multi?layered London in a way it has never been seen before.

The competition is open to students and illustrators throughout the world, with the deadline being Friday April 6. The top 50 entries selected by a panel of judges will be displayed in an exhibition at London Transport Museum that will open Tuesday 13 November and run until Monday 10 December 2012.

Last year, the top prize was won by up-and-coming illustrator Anne Wilson (below). We interviewed her about her winning entry here.