Boris Johnson rules himself out from UK Prime Minister Seat

In a surprise announcement, the former Mayor of London said he would “support” the next Tory leader but that it would “not be me”.

Mr Johnson gathered the media for a speech at a central London location for what was expected to be his campaign launch.

However, after giving a speech outlining his view that the next Prime Minister should champion the "forgotten" people in Britain, he ruled himself out for the top job.

“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," he said.

“My role will be to give every possible support to the next Conservative administration to make sure that we properly fulfill the mandate of the people that was delivered at the referendum, and to champion the agenda I believe in – to stick up for the forgotten people in this country.”

Mr Johnson has long been the favourite to succeed David Cameron, who stepped down after being defeated in the European Union referendum.

However, his campaign was dealt a fatal blow this morning after his former Vote Leave ally Michael Gove announced that he was standing as a leader.

In his announcement speech, Mr Gove said he did not believe Mr Johnson could be trusted to unite the Conservative party and lead the country.