BORIS Johnson is the runaway front runner to become the next Tory leader - and Prime Minister - in what will undoubtedly be a bitter contest to succeed David Cameron.

The leading Eurosceptic MP is the darling of the party's rank and file, as well as the bookmakers' odds-on favourite, in the race triggered by Cameron's resignation in the wake of Friday’s Brexit result.

The Conservative backbench 1922 Committee will meet tomorrow to determine the timetable for the internal contest, which will see MPs whittle down candidates to two to put to the membership.

Tory sources believe that, given the referendum result, only a pro-Brexit MP will be palatable to party members and the country. The winner will automatically become Prime Minster as leader of the governing party.

Johnson, a two-term Mayor of London, is believed to have a political appeal beyond core Tory supporters. However, Alan Duncan, a pro-EU Tory MP, has questioned Johnson’s fitness to be leader:

"Do not necessarily assume that he is the darling of the Conservative Party activists. A lot of them have loved the notoriety and the excitement. But actually, once you scratch the surface a little bit and ask the second question, a lot of them don't want a permanent ride on the big dipper."

The most credible ‘stop Boris’ candidate appears to be Home Secretary Theresa May, who campaigned for EU membership without alienating Brexit supporters. A majority of the Conservative group at Westminster backed Remain and her pro-EU credentials should ensure that she also makes the run-off.

Brexiters Michael Gove and former Defence Secretary Liam Fox may also be potential contenders, although Gove has previously said he will not run. Education Secretary Nicky Morgan and Energy and Climate Change Secretary Amber Rudd are also in the frame..

In a televised debate during the referendum Rudd famously aimed a dig at Johnson: “Boris, well, he’s the life and soul of the party, but he’s not the man you want driving you home at the end of the evening.”

George Osborne, who is the Prime Minister’s closest colleague, is not expected to be a candidate.

The Chancellor was last year considered to be potential replacement for Cameron, but his political stock has plummeted lately. He was criticised for trying to cut disability benefits and tax credits for the working poor and slated for his apocalyptic warnings during the referendum. He is also expected to leave the Treasury in a cabinet reshuffle.

Defence Secretary Michael Fallon denied the government is a rudderless ship after Cameron's resignation statement. Speaking at an Armed Forces Day event in Cleethorpes, he said: "The Prime Minister goes on, the government goes on until the Autumn, until there's a new leader and a new government. We'll remain at our posts and we have a big agenda. We were elected only a year ago and we've set out fresh legislation which we're taking through parliament at the moment."

He also warned that Brexit would take time to achieve. "Leaving the European Union is not an easy or a quick business. It's not been done before. Obviously it's going to take time for the details to be worked out but that's a matter now for the next prime minister and the new government in October."

The impact of the referendum vote would have no effect on the UK's armed forces or security, he added: "I've spoken yesterday to all our key allies and to the Secretary General of Nato to reassure them that we will continue our work internationally."