Boris Johnson, the very public face of Brexit and the man most Britons thought would succeed David Cameron as prime minister, has ruled himself out of contention, the apparent victim of a Tory double-cross that Francis Urquhart, the antihero of the 1990s BBC drama House of Cards, might have engineered himself. The Labour Party is in similar turmoil, with its MPs having passed a vote of no-confidence in Jeremy Corbyn's leadership by a margin of 172-40.

More than 1.5 million people have signed a petition demanding a second EU referendum, the pound has yet to recover from its biggest plunge in 50 years, and two rating agencies have downgraded Britain's AAA credit rating. Across the Channel, the EU appears in no mood to bestow any parting favours on Britain. German Chancellor Angela Merkel reaffirmed this on Tuesday, declaring that if Britain wanted to do away with the responsibilities of membership it could not expect be able to keep any of the privileges.

Mr Johnson and his chief ally in the Brexit campaign, Michael Gove, seem not to have had an agreed-upon contingency plan for just this sort of reaction – a quite extraordinary state of affairs. There's speculation Mr Johnson may have been maneuvering to row back from a complete separation from the EU and that Mr Gove had sensed his wavering resolve. Nonetheless, the justice secretary's decision to withdraw his support for Mr Johnson's leadership bid and to announce his own candidacy shortly after was unexpected. Just before the June 23 referendum, Mr Gove said in a newspaper interview that "I don't think I have got the exceptional level of ability required for the job [of prime minister]". Francis Urquhart himself could not have been more dissembling.

Home secretary Theresa May is considered to be Mr Gove's chief rival for the job, despite having advocated remaining in the EU – though not with any degree of enthusiasm. Her recognition that the die is cast and that Britain must move forward is not in doubt, however. On Thursday she said "Brexit means Brexit" and she pledged to negotiate a "sensible and orderly" departure. Given the level of anger within Conservative ranks about Mr Gove's betrayal, Ms May must be considered the new favourite to succeed Mr Cameron, although charges she failed to reduce net immigration while home secretary may count against her.

If Mr Johnson's sudden transition from political rooster to feather duster has saddened his many millions of supporters, there's an element of poetic justice about his humbling. He had been broadly supportive of Britain's place in Europe before the referendum, and was expected to fight the campaign by Mr Cameron's side. But sensing an opportunity for quick political glory and advancement, Mr Johnson chose the leave camp (apparently at Mr Gove's strong urging). It's conceivable that had Mr Johnson channelled his energy and charisma towards Remain, the referendum would not have carried.

Residual affection for Europe (and perhaps a twinge of remorse over his rank opportunism) may have been a factor in Mr Johnson's reticence to prosecute a quick divorce to the satisfaction of more committed Brexiteers such as Mr Gove. It's cost him the prime ministership, however. Likeable and smart as Mr Johnson is, the prospects of a comeback look remote.

Britain is now essentially leaderless, and will remain so until September 9 when the Conservatives are expected to wrap up their selection process. That long hiatus prompted Bank of England governor Mark Carney to announce on Thursday that he was ready to cut interest rates and ramp up quantitative easing to ensure Britain did not fall into recession. For so long as the political vacuum at Westminster continues, however, the economy will be hostage to falling business confidence and a leakage of investment.

For a nation that still celebrates the successful strategic withdrawal of Dunkirk in World War II, the irony of Brexit catching the British political establish so badly unprepared is rich.