Boris Johnson pulls out of race to be Britain's Brexit PM

Former mayor of London Boris Johnson on Thursday ruled himself out of the race to succeed Prime Minister David Cameron on a day of high drama following Britain's shock vote to leave the EU. The decision by Johnson, who spearheaded the "Leave" campaign, upended the Conservative Party leadership contest and added to deep uncertainty over how and when the country will split from the bloc. Johnson had been tipped as a favourite to succeed Cameron, who resigned after the June 23 referendum saying he would leave it to his successor to begin formal talks with the EU on Britain's departure -- despite European leaders insisting on a quick divorce.