In the two years since the nation voted to leave the European Union, the Conservative party has consistently put politics before country by failing to come forward with a credible Brexit plan. The Tories have also failed to resolve the questions about inequality and powerlessness that were thrown up in too many parts of the country by the poll in June 2016. Instead we have had Theresa May conduct months of parallel negotiations – one set at home and one abroad – to get to a position where this country’s long-term post-Brexit relationship with the EU remains a riddle waiting to be solved.

Mrs May has yet to convince her colleagues that she has a workable plan for what happens when this country leaves the EU, let alone where it is eventually going. The ambiguity is the point: Mrs May’s pitch to the Brexiters is that they ought to wear her temporary fudge while a Canada-style free-trade deal is negotiated. By this ruse Mrs May clings to power. She does not deserve to. The last Labour prime minister, Gordon Brown, today aptly quoted Winston Churchill in a thoughtful speech to describe, accurately, Mrs May as being “decided only to be undecided, resolved to be irresolute, adamant for drift, solid for fluidity, all-powerful to be impotent”.

It is not as if Brussels won’t do a deal. It’s just that for Mrs May it must be so vacuous that it will be meaningless. There is no clarity over what the UK’s connection with the single market will be; nor whether it will be in a customs union or not; nor if Brexit Britain will have a concrete plan for dealing with concerns about migration. Yet this suits Mrs May, who prefers to stay in office with a fix than go down fighting for a principle. Such a strategy relies on continuing with an inward-looking, divisive and ultimately corrosive politics.

By law, Mrs May’s government cannot sign a Brexit deal without MPs’ approval. The prime minister hopes a text coupled with a this-deal-or-no-deal choice will concentrate minds. But it seems fairly clear that no majority exists in the Commons for any version of her Brexit plan. If the prime minister’s deal is rejected, parliament must take back control. There is no duty on MPs to vote for a bad deal. The circumstances of a defeat would frame the response. Mr Brown was right to say that MPs must be able to vote on amendments before giving a thumbs-up – or a thumbs-down – to a future Brexit arrangement. It would be wrong to subvert a “meaningful vote” by rigging the parliamentary process – and this must be resisted.

If MPs say the deal is not good enough and ask ministers to return to Brussels to get a better one, even if that requires more time to do so, then that is what Mrs May must do. This might cost her the leadership – though given her instincts for self-preservation she might call the bluff of Tory hardliners by withdrawing article 50 to head this off. Given past events, it would be unwise to discount the improbable as impossible. Key will be Labour’s response: it could offer its own softer version of Brexit and seek support from Tory MPs. It is hard to see how the Conservative benches would support a Labour plan after rejecting their own leader’s proposal. But we live in interesting times.

The impression is of a never-ending Brexit crisis, one that erodes trust in democracy. Mr Brown thinks the situation could become so dire that Britain will end up holding a second referendum – with the prospect of this country rejoining the EU in the future. It is significant that three out of four living former prime ministers – Mr Brown, Tony Blair and John Major – alight on a national plebiscite to solve the Brexit conundrum. This is not without considerable risks. The Tories spent months saying no deal is better than a bad deal. The British public might, given the chance, take them at their word. If MPs were to refuse to support a Brexit plan, or to ask for more time to get a better deal or to vote for a general election, there would be chaos. Given those foreseeable circumstances, it would be foolish to rule out another referendum.