Boris Johnson
Mayor of London Boris Johnson(Reuters)

Former London mayor Boris Johnson shocked spectators today as he abruptly announced his decision to pull out of the race for the post of UK prime minister.

"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 the person cannot be me," Johnson said while stunning the attendants of the news conference in a London luxury hotel.

Johnson, whose support of the Leave cause is considered integral to the Brexit vote, saw his bid suddenly crumble after several leading Conservatives questioned Johnson's credentials and capability to lead the UK out of its current crisis.

Some conservative lawmakers also suggested that Cameron loyalists refused to support Johnson after he defied Cameron by backing the Leave campaign. Hence Johnson called off his bid after he realized that lawmakers had defected from his campaign overnight.

But the final nail in the coffin was delivered by his Brexit campaign ally, Justice Secretary Michael Gove, who withdrew his backing and announced his own leadership bid

Despite having previously said he would back Johnson, Gove backtracked when he wrote that he had come "reluctantly, to the conclusion that Boris cannot provide the leadership or build the team for the task ahead" in an article in the Spectator magazine.

Crispin Blunt, a senior Conservative lawmaker also suggested that Gove had probably withdrawn his support because Johnson refused to promise him a job.

Johnson's withdrawal however makes Theresa May, the interior minister who backed remaining in the EU, the new favorite to succeed Cameron.

"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."

In an article in the Times newspaper, May had also fired shots at Johnson's persona by saying government was not "a game".

In addition to May and Gove, the candidates are Stephen Crabb, the cabinet minister responsible for pensions, Liam Fox, a right-wing former defense secretary, and Andrea Leadsom, a minister in the energy department.

Conservative Party lawmakers will eventually trim the five leadership candidates down to two, and party members will then vote on which of them will become party leader and presumptive prime minister.