Controversial Conservative MP Boris Johnson has confirmed he is to enter the race to become the Tories’ London mayor candidate.

The party will select its candidate from more than 40 applicants via a series of challenges. Around 10 will be interviewed this weekend, with a shortlist of up to five taking part in an ‘open primary’ of all London voters in September. Johnson has stood down from the shadow cabinet but will remain MP for Henley.

Current mayor Ken Livingstone has confirmed he will be standing for a possible third term in next year’s election, while the Green Party has put forward anti-4×4 campaigner Sian Berry as its candidate. The LibDems are yet to confirm a competitor.