Their double act had been central to the push for Leave, a Tory alternative to the nationalistic bombast of UKIP's Nigel Farage, with Mr Gove perceived as bringing the brains and Mr Johnson the sales pizazz. Former London mayor Boris Johnson waves after announcing he will not run for leadership. Credit:AP Mr Johnson's campaign for the leadership – which had Australian political strategist Sir Lynton Crosby on board - faltered in a disastrous post-referendum week that saw Mr Johnson first take a day off to play cricket, then pen a newspaper column derided for its disconnect with the tumult in the markets and the currency. Mr Gove, who has given repeated interviews saying he didn't have the constitution for leadership, had been expected to back Boris as the next Conservative leader and prime minister. But instead, in a stinging rebuke, he issued a statement on Thursday saying he had "reluctantly but firmly" concluded that Mr Johnson was not capable of uniting the party or the country.

In his speech announcing he would not run, Mr Johnson quoted from Shakespeare's Julius Caesar. Boris Johnson ended his leadership bid for the Conservative Party before it even began. Credit:Bloomberg He cast Mr Gove as Brutus and himself as the betrayed Caesar, saying it was "a time not to fight against the tide of history but to take that tide at the flood and sail on to fortune". Mr Johnson's father, Stanley Johnson, told the BBC: "Et tu, Brute is my comment on that." Once Michael Gove declared, Boris was dished. Credit:Jack Taylor

Mr Johnson's allies were also furious at the betrayal, with Tory MP Jake Berry tweeting "there is a very deep pit reserved in hell for such as he". Mr Johnson had faced a tough battle for the leadership. Though he is popular with the party members, who get the final say, he is not popular with the press. Dressed in head-to-toe tartan: Britain's Home Secretary Theresa May launches her leadership bid for Britain's ruling Conservative Party in London. Credit:Matt Dunham If we are to make the most of the opportunities ahead we need a bold break with the past. Michael Gove

Mr Gove, who is married to a Daily Mail columnist, has declared receiving gifts and the hospitality of Mail proprietor Lord Rothermere and who attended Rupert Murdoch's wedding, had probably expected tabloid support for his leadership bid. But in yet another knifing, the irony-free Daily Mail declared on its Friday front page that it had been a "Tory day of treachery", with "a party in flames [in the] most savage bloodletting since the fall of Thatcher", and concluded "it must be Theresa [May for the leadership]". "This was, surely, one of the most unedifying days in modern politics. A day of treachery and opportunism on both sides of the Chamber. A day in which the currency of political discourse was devalued still further," the paper editorialised. "The Tories, who only 14 months ago won a famous victory, are tearing themselves to pieces, while an Opposition that defies parody engages in a gruesome civil war." Mr Johnson said it was vital "we bring together everyone who has campaigned for Remain and Leave … this is our chance to unite our party and at the same time unite our country and our society".