Stop the clock. The UK has two years to negotiate the terms of its exit from the European Union – less, in fact, because the countdown started in March, when Theresa May activated article 50 of the Lisbon treaty. She decided shortly afterwards that she could afford the luxury of a few weeks campaigning in a general election, which would then afford her a gargantuan mandate to finish the job at her leisure and on her terms.

If the Conservatives have been deprived of a majority – or even if May ends up able to control the Commons by a wafer-thin margin – her judgment looks catastrophically faulty. The authority she had a few months ago, predicated on a role she cast for herself as the woman to get on the with the job, the undisputed Empress of Brexit, will be shot. The usual caveats about waiting for the definitive result must be added, but as things stand she surely cannot boast the credentials to lead Britain through the most challenging political and diplomatic task it has faced in generations. And the talks are due to begin within a fortnight.

The 'Brexit election' became an exercise in national denial of what Brexit might really involve

That is not to say that the British public has retracted the instruction that was given in last year’s referendum. Whatever the final result, it appears that the two main parties have scooped up around 80% of the vote – and Labour’s position on Brexit is acquiescence to the idea, coupled with vagueness on detail to match that of the Tories. Jeremy Corbyn’s manifesto conceded that Britain would relinquish full membership of the single market. There is nothing in the results so far that might be read as a distinct assertion of dissent by the 48% who voted remain last June. The Liberal Democrats tried to capitalise on their anxiety, yet Tim Farron’s party has shed votes to Labour – costing Nick Clegg his seat in Sheffield – and been overrun by Tories elsewhere.

And yet a strong performance by Labour looks likely to have been powered by the enthusiastic endorsement of younger voters who, while perhaps not primarily animated by EU matters, are broadly more pro-European than their seniors. The result also indicates a level of organised resistance to the prospect of being governed by a Tory party that has co-opted a style and agenda that were once the property of Ukip. In other words, 8 June 2017 looks set to herald a new chapter in British culture wars that must, in part, be seen as a rebuke to the idea that May’s Brexit agenda is the only available path. That is true even if she continues as prime minister.

It was a failing of both main parties that the campaign did not interrogate the practical reality of leaving the EU; that the “Brexit election” became an exercise in national denial of what Brexit might really involve. May hoped to avoid that discussion, and Corbyn judged, correctly it seems, that pro-Europeans appalled by the trajectory on which the Tories had set the country had nowhere else to turn but Labour if they wanted to apply the brakes.

Every election tells one big story containing multiple subplots, and it will take days, perhaps months, to unravel the various strands. Many leave voters, formerly Labour supporters, in the north of England appear to have acted as was predicted months ago and taken their Euroscepticism to the Tories – but not by big enough margins for scores of seats to change hands. Meanwhile, the anti-Conservative vote elsewhere has found its expression in swings to Labour that were not widely foreseen. Ukip’s support has dissolved. But it is fair to presume that those voters are still ardent in their belief that Britain must assert tighter control over immigration and that quitting the EU is their preferred mechanism.

Until these complex messages can be properly deciphered it is impossible to say that British opinion on the single biggest issue facing the country has shifted. But it is just as implausible to assert that the timetable adopted by Theresa May is viable. It was the Tory leader who placed her capacity as the supreme guardian of Brexit on the ballot paper. It was she who started the clock running and then complacently instructed the British people to grant her unlimited freedom of manoeuvre. Other EU leaders were supposed to wait patiently and, in due course, be overawed by the commanding support that the newly emboldened prime minister would bring to the negotiating table. But her handling of the campaign refuted the premise on which it was based. The “strong and stable” message soured and then curdled amid serial U-turns, brittle stump performances and relentless negativity towards her Labour rival.

The prime minister evacuated her stores of credibility and her reputation for competence at a rate rarely witnessed in British politics. Even the most passionate opponent of Britain’s EU membership will now query her qualifications as a formidable handler of the imminent negotiations. And the idea that this process can start later this month – that “Brexit means Brexit” is sufficient basis on which to proceed – is untenable. It isn’t even clear what kind of government the UK will have or who will be leading it.

This unravelling will be watched with shock, dismay and a large dose of schadenfreude in other European capitals. Viewed from the outside, Britain’s decision to start the clock ticking and then digress into an election that did not even address the fundamental questions of what was at stake looked perverse, if not downright dangerous. That tick-tock counting down towards March 2019 required urgency when parliament was dissolved. In a parliament where no party can command a reliable majority it will sound ominous; it is the sound of an alarm about to ring.