Race Opens to Succeed Cameron amid Brexit Disarray

The race to choose a successor to Prime Minister David Cameron got under way Wednesday after last week's stunning Brexit vote, with former London mayor and top "Leave" campaigner Boris Johnson tipped as the narrow frontrunner.

With turmoil surging through both of Britain's main parties, defiant opposition Labor chief Jeremy Corbyn meanwhile faced a looming leadership challenge after last Thursday's referendum.

Johnson, who led the "Leave" campaign to victory, tops the opinion polls along with interior minister Theresa May for the Conservative leadership.

But the first to throw his hat into the ring was work and pensions minister Stephen Crabb, a virtual unknown to the British public.

The 43-year-old called on the party to "get past this Boris/stop Boris dichotomy," in reference to the divisive Johnson.

The party will official open nominations at 5.00pm (1600 GMT). Johnson and May are expected to announce their bids Thursday, before nominations close at noon.

The new leader, who will be chosen by a postal ballot of party members currently numbering around 150,000, is expected to be announced on September 9.

- Boris bookies' favorite -

Bookmakers make Johnson slight favourite over May, and The Sun newspaper reported Wednesday that he had already secured the backing of 100 of the Tory MPs who will vote next week to whittle down the field to two nominees.

The ConservativeHome blog surveyed more than 1,300 members and found the slimmest of leads for May, mirroring the results of a YouGov poll published Tuesday.

Pro-EU finance minister George Osborne, long seen as a possible Cameron successor, has ruled himself out.

Critics have questioned whether the "Leave" camp -- and Johnson in particular -- has any idea how to manage the unprecedented situation left by last week's vote.

"He has still to offer anything like a concrete plan on how he would negotiate the post-Brexit future," wrote former BBC political editor Nick Robinson.

The political chaos was not confined to the ruling party, with opposition Labor leader Corbyn arming himself for battle against a huge majority of his own MPs.

Corbyn was defeated by 172 to 40 in a non-binding no-confidence vote held by Labor lawmakers late Tuesday, and speculation was mounting that a candidate would come forward and challenge him.

"It looks as though we will have a leadership election now," Corbyn loyalist and shadow finance minister John McDonnell told reporters Wednesday.

Media reports suggested that his former business spokeswoman Angela Eagle could be preparing to launch a bid.

- For heaven's sake, go! -

Even Cameron weighed in, telling Corbyn "for heaven's sake man, go!" during parliament's weekly Prime Minister's Questions session.

That followed former leader Ed Miliband's declaration that he had "reluctantly reached the conclusion that his position is untenable."

Corbyn is due later Wednesday to rally trade unions and the Labor members who helped him win last year's leadership vote by a landslide margin, and a fierce battle is looming over who owns the soul of the party -- parliamentarians or members.

"I was democratically elected leader of our party for a new kind of politics by 60 percent of Labor members and supporters, and I will not betray them by resigning," the 67-year-old self-declared pacifist said in a statement.

- Apocalypse -

The Labor turmoil comes amid speculation that Cameron's successor as Conservative leader and prime minister may be tempted to call an early election later this year.

Labor, which has lurched to the left under Corbyn's leadership, is viewed by some as unelectable in a general election while he remains in charge.

Former foreign minister Jack Straw said his party faced an "apocalypse" if an election was held with Corbyn still in office.

"It's probably the worst crisis since Labor’s formation," he told Sky News.

The leadership ructions of both parties dominated the front pages of Wednesday's newspapers, with the Metro calling on Corbyn to "Please Jez go!" and The Sun declaring it "Boris day".

In a sign of the depth of the crisis, the Scottish National Party, which has 54 seats in the House of Commons to Labor’s 229, announced it would make a bid to take over as the official opposition party in parliament.