Things just got a lot worse for David Cameron, because Boris Johnson

Boris Johnson has announced he will, "in all probability", stand for election as an MP next year.

"I have not got any particular seat lined-up but I do think... in all probability I will try to find somewhere to stand in 2015," the mayor of London said during a Q&A session after a speech in the capital.

He added that he intended to serve out his full term as mayor, which runs until 2016, and raised the prospect of his plan to run as an MP "going badly wrong".

Johnson was MP for Henley between 2001 and 2008 before stepping down to run for mayor.

He is widely regarded as a potential successor, or even challenger, to David Cameron as leader of the Conservative Party.

The prime minister is not having a great week after Baroness Warsi's shock resignation over his stance on Gaza.

His reaction to Johnson potentially returning to the Commons?

Hm...