On Tuesday evening the Commons witnessed a scene worthy of a cliffhanger finale to a blockbuster television series that we all know will resume in the autumn. Just before 7pm, with all Theresa May’s enemies closing in for the kill after a long and engrossing buildup, Tory MPs produced a twist in the plot. They saved the prime minister’s skin at the last minute by voting not to keep the UK inside the EU customs union after Brexit. As the Commons chamber emptied and the credits metaphorically rolled, a government whip rose and announced that the summer recess was now not going to be brought forward after all.

May sees off rebellion on customs union as amendment is defeated Read more

With one mighty bound, it seemed, May was free. She lives to star in another series. But for how long? Yesterday the reprieved prime minister celebrated with one of her best sessions at prime minister’s questions in a while. But the Brexit faultline inside the Tory party was still plain to see. The recently resigned ministers David Davis and Steve Baker asked pointed questions that tee up fresh plot lines for September, while leave obsessive Andrea Jenkyns was bombarded with prime ministerial hate rays for asking sarcastically at what point Brexit had become remain.

Two hours later Boris Johnson delivered a personal statement to MPs that also contains clues about how the autumn may evolve. By his standards, it was a carefully crafted, even austere statement, and May will surely be relieved that it – sort of – expressed support for her general approach to Brexit and to her leadership. But its key message (summed up in Johnson’s view that “It is not too late to save Brexit”) is in fact a call to arms, tipped with the venom of implied betrayal, for leavers to make life hell for May when parliament returns. Though Johnson did not explicitly raise the question of a party leadership challenge, his statement was a declaration that he stands ready. When Johnson offers you loyalty, watch your back.

Few things in life are wholly without precedent. A Conservative government struggling to survive in the face of its own divisions over Europe is not one of them. When Ian Blackford yesterday accused May of being in office but not in power, the SNP MP was repeating the words used by Norman Lamont when he was sacked as John Major’s chancellor a quarter of a century ago. “We give the impression of being in office but not in power,” Lamont said then, before finishing his speech with words that seem spookily relevant again today: “Unless this approach is changed, the government will not survive, and will not deserve to survive.”

Facebook Twitter Pinterest Edward Heath addresses the nation in a party political broadcast on the eve of the general election of February 1974. Photograph: Frank Tewkesbury/Getty Images

The Major government did survive, after a fashion, for another four years. Yet the newspapers that carried pictures yesterday showing May behind bars in their morning editions yesterday were not wrong. She remains a prisoner, trapped by her party’s divisions, unable to command the Commons and at odds with the EU over Brexit terms. May won a very important vote over the pro-EU rebels on Tuesday on the trade bill. But she made sizeable concessions to her right wing on Monday over the customs bill, exacerbating the already bitter mood in the party. The Tory remainer Anna Soubry has made clear that she is not in conciliatory mood: “The problem is, I don’t think that she’s in charge any more,” Soubry told Radio 4’s Today programme. “I’ve no doubt that Jacob Rees-Mogg is running our country.”

This too is another echo of a past Tory failure. You have to be in your 60s now to remember much about the February 1974 general election, in which Edward Heath’s Tory government fought an early election in the middle of a miners’ strike – using the slogan (though Heath himself did not actually use it) “Who governs?”. The public’s answer, when the votes were counted, was that Heath didn’t. His demand for a new mandate proved to be his downfall. May made a similar sort of mistake in 2017 but survived. Yet for May’s government to have got itself into a position in which its own backbenchers are asking who is in charge is not a good look.

“There’s a last-days-of-Rome feel to things,” a Tory backbencher said this week. That’s self-important English public school exaggeration. Most European countries, including Britain, have been fairly well governed by weak governments for decades – and still are. Even so, May’s grip on parliament over Brexit is clearly weakening as the moments of decision press in on her. Her Chequers deal and the subsequent white paper are an attempt to unite Tory MPs around a compromise they don’t all want, and the EU is unlikely to endorse. It’s a compromise based on the admission that Britain’s post-Brexit relationship with the EU takes precedence over unilateralist fantasies. The Rees-Moggs of the Tory party simply do not accept this.

The question at the root of our political discontents​ remains: can referendums coexist with representative democracy?

A characteristically more insightful Tory view came this week from Justine Greening, the former education secretary, who said that “parliament is stuck in a stalemate”. It is stuck for several intertwined reasons: partly because Brexit is complex, partly because the Tories are divided, and partly because we have a hung parliament. Fundamentally, though, it is stuck because British democracy has not worked out how to reconcile the plebiscitary mandate of referendums with the representative parliamentary system dominated by political parties. As Greening herself observed , parliament is not set up to cope with democracy by referendum. The events of the past two years - and of the past two weeks in particular - have underlined the truth of that.

When Heath asked “Who governs?”, the question was anchored in class politics: was it the elected government and parliament in Westminster, or the extra-parliamentary power of the miners’ union. The answer was an elected government – formed by Harold Wilson’s Labour – that would make peace with the miners. When the “Who governs?” question is asked today, however, the choice is different. Is it the elected government and parliament at Westminster, or a referendum verdict? That’s a more difficult question to answer than the one that Heath posed.

Last week, amid the mayhem of the Chequers fallout over Brexit, the Trump visit and the climax of the World Cup, few will have noticed the publication of the report of the Independent Commission on Referendums by the Constitution Unit at University College London. Few launches can have been worse timed. But the 224-page study by a group of commissioners is one of the very few serious attempts to get to grips with the question that remains at the root of our present political discontents: whether referendums can coexist with representative democracy.

Until Britain can find the answer, the stalemate is likely to continue. Join us again in September to see if Britain’s politicians can come up with the answer that has eluded them for so long.

• Martin Kettle is a Guardian columnist