Boris Johnson quits race for UK Prime Minister

Former London mayor Boris Johnson, runaway bookmakers' favourite to become Britain's prime minister, abruptly pulled out of the race on Thursday in a shock announcement less than a week after leading the campaign to pull the country out of the European Union.

Johnson's announcement, to audible gasps from a roomful of journalists and supporters, was the biggest political surprise since Prime Minister David Cameron quit on lat Friday, the morning after losing the referendum on British membership in the bloc. Johnson's withdrawal makes Theresa May, the interior minister who backed remaining in the EU, the new favourite to succeed Cameron. She announced her own candidacy earlier on Thursday, promising to deliver the EU withdrawal voters had demanded, despite having campaigned for the other side."Brexit means Brexit," she told a news conference.

"The campaign was fought, the vote was held, turnout was high and the public gave their verdict. There must be no attempts to remain inside the EU, no attempts to rejoin it through the back door and no second referendum."

Johnson, whose support of the Leave cause was widely seen as delivering its victory, saw his bid suddenly crumble after his Brexit campaign ally, Justice Secretary Michael Gove, withdrew his backing and announced his own leadership bid. "I must tell you, my friends, you who have waited faithfully for the punchline of this speech, that having consulted colleagues and in view of the circumstances in parliament, I have concluded that person cannot be me," Johnson said at the news conference in a London luxury hotel.

Supporters in parliament, who had gathered expecting to hear him formally announce his candidacy, were left stunned.

Gove, a close friend of Cameron's despite differences with the prime minister over Europe, had previously said he would back Johnson. But in an article in the Spectator magazine on Thursday, Gove wrote that he had come "reluctantly, to the conclusion that Boris cannot provide the leadership or build the team for the task ahead".

Conservative lawmakers said Johnson may have been undone by supporters of Cameron exacting revenge for his decision to defy the prime minister and back the Leave campaign.

"He who lives by the sword, dies by the sword," said one lawmaker, describing internal party conflict on condition of anonymity. The lawmaker told Reuters that Johnson had realised his bid would fail after lawmakers defected from his campaign overnight.

Johnson became the latest political casualty of a civil war in the ruling party unleashed by Cameron's decision to hold the referendum on membership in the EU, an issue that divided the Conservatives for decades and now divides the country.