Cameron may have challenger as Johnson throws hat in the ring

London mayor Boris Johnson has declared his intention to stand for parliament at next year’s general election, putting an end to months of speculation about his ambitions for a return to Westminster.

Prime Minister David Cameron was quick to welcome the announcement, saying he had always wanted to see “my star players on the pitch” during the forthcoming election campaign.

However, Johnson’s declaration immediately raised the prospect that he could emerge as a rival for the Conservative leadership if the party is defeated — or again fails to secure an overall Commons majority — at the polls.