It says something about the unknowability of history that, this late in the day, the nation is poised between two such different paths. In the past few weeks I have alternated between thinking Theresa May is likely to get her Brexit deal through parliament and that we will never leave the EU.

This weekend I think the most likely outcome is that we will stay. I had thought the prime minister unlikely to win the vote on her deal on Tuesday, and nothing happened this week to change that assessment.

Geoffrey Cox, the attorney general, returned from Brussels empty-handed, and May travelled all the way to Grimsby to say nothing new, except to plead with EU leaders to help her.

The prime minister may travel to Brussels on Sunday or Monday. There will be a legally binding document of some kind. There may even be a completely coincidental announcement that extra spending on schools and hospitals in Northern Ireland will continue after the expiry of the Conservative Party’s two-year deal with the DUP in June.

The DUP may decide at the last moment to support the deal. But even then the prime minister needs another 106 MPs who voted against the deal last time to change sides. That means, for example, 73 Conservatives and 33 Labour MPs. Those are what nowadays are called “challenging” targets.

Britain Before Brexit: Northern Ireland Show all 12 1 /12 Britain Before Brexit: Northern Ireland Britain Before Brexit: Northern Ireland Derry, Londonderry A garage door displaying unionism, bolted shut, like a visual representation of Brexit Britain, locked to outsiders, safeguarding what’s inside Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Derry, Londonderry Rossville Street, the site of Bloody Sunday, where messages demand a severance with England. From this perspective, Britain is England in sheep’s clothing, the real empire, the centre of colonial power Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Bangor A political message in paint not yet dry, still forming, setting, adjusting, or in old paint finally eroding, melting away Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Bangor Moral judgement frames a residential view. The message seeks to make everybody involved in the religious narrative: those who don’t believe are those most in debt Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Castlerock The beach is sparse and almost empty, but covered in footprints. The shower is designed to wash off sand, and a mysterious border cuts a divide through the same sand Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Belfast Two attempts to affect and care for the body. One stimulated by vanity and social norms and narratives of beauty, the other by a need to keep warm in the winter night Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Belfast The gate to an unclaimed piece of land, where nothing is being built, where no project is in the making, where a sign demands the creation of something new Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Derry, Londonderry Under a motorway bridge a woman’s face stares, auburn and red-lipped, her skin tattooed with support for the IRA and a message of hostility to advocates of the Social Investment Fund Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Derry, Londonderry The Fountain Murals, where the curbs and the lampposts are painted the red, white, and blue of the Union Flag. A boy walks past in the same colours, fitting the scene, camouflaged Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Coleraine A public slandering by the football fields, for all to see or ignore. I wonder if it’s for the police or for the community Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Belfast A tattoo parlour, where the artist has downed tools, momentarily, bringing poise to the scene, which looks like a place of mourning, not a site of creation Richard Morgan/The Independent Britain Before Brexit: Northern Ireland Derry, Londonderry A barrier of grey protects the contents of this shop, guarding it from the streets outside, but it cannot conceal it completely, and the colours of lust and desire and temptation cut through Richard Morgan/The Independent

Theresa May is paying the price for saying different things to different audiences. In Grimsby on Friday she was still trying to scare Labour MPs into voting for her deal by saying it was better than a no-deal Brexit. In the next sentence, she was trying to scare Tory MPs by saying the alternative to her deal was that “we delay Brexit and carry on arguing about it, both amongst ourselves and with the EU”.

Naturally, Labour MPs hear the message intended for Tories, and vice versa. Labour MPs think, “Why should we vote for the deal when we could delay Brexit, possibly for ever?” And Tory MPs think, “No-deal Brexit is what my local association wants.”

Not only is May’s two-faced message counterproductive, however, but it is wrong. She has already in effect ruled out leaving the EU without an agreement. Some of the no-deal Brexiteers have been slow to appreciate the significance of her statement on 26 February. She promised a vote in the Commons and said: “So the UK will only leave without a deal on 29 March if there is explicit consent in this house for that outcome.”

Such consent could not conceivably be forthcoming: there is a large majority in the House of Commons against a no-deal Brexit. This majority would prevail even if May were to split her cabinet and government by trying to whip her MPs to vote for a no-deal Brexit, which she will not.

If, therefore, the Brexit deal is defeated on Tuesday, the Commons will vote against a no-deal exit on Wednesday and will then move on to a third vote, on the question of whether the prime minister should ask the 27 countries of the EU for more time. It is possible that MPs might vote against all three options, but there are only two capable of gaining a majority. Even if it takes repeated votes, parliament will have to decide either to leave with the deal or to delay Brexit.

If MPs vote for delay, Theresa May has undertaken to act on it. I think the EU27 would agree to extend the deadline, although we cannot be sure for how long or on what terms.

If we never leave the EU, that is how it will happen. After Brexit has been delayed once, parliament will face essentially the same choice two, three, nine or 21 months later. Once we have delayed long enough, a new referendum will be a possibility.

Some Conservative MPs think we could have a short delay and then leave without a deal in June. They are not paying attention. Parliament won’t vote for it now and it won’t vote for it then.

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Other Tory MPs take a harder line. For them, the prime minister’s deal is not Brexit. It is “Remain by another name”. It would be worse than staying in the EU. They don’t want ever to leave on those terms.

Personally, I think delaying Brexit would be a bad decision, because the prime minister’s deal is a sensible compromise that respects the referendum and keeps us close to the EU economy. I think Tory no-dealers are fanatics who would rather destroy what they have worked for than accept any impurity or compromise. And I think most Labour MPs who vote against the deal are breaking promises they made to honour the referendum.