Boris Johnson is heading for a landslide victory – and then disaster

Surely it would be hard to stop a determined prime minister from taking Britain out of the EU without a deal?

There is only one question in British politics at the moment. Can a no-deal Brexit be stopped? Yes it can, and so Boris Johnson is set to become prime minister on a false prospectus.

According to YouGov, 74 per cent of Conservative Party members intend to elect him as leader – on a pledge to leave the EU, deal or no deal, on 31 October. That is a promise he cannot guarantee to deliver.

This has been pointed out repeatedly, and the Tory leadership campaign has continued serenely on – untroubled by reality, buoyed by the power of simple assertion. Johnson says he’ll do it, “do or die”, and the party members clap and cheer, as if to drown out the voices of doubt in their heads.

Jeremy Hunt, instead of telling the truth, has appeased the delusion by toughening up his own language, saying that, if a Brexit deal is not in prospect at the end of September, he will take us out without a deal too. His reward for such cowardice will be a drubbing without honour.

Johnson’s blithe assertion that the world is as he wants it to be has confused people. Surely it would be hard to stop a determined prime minister from taking Britain out of the EU without a deal? So it is worth setting out, again, how parliament can prevent such an outcome.

Philip Hammond, the chancellor, discussed plans this week with fellow opponents of a no-deal Brexit in his office in the House of Commons. I have no inside intelligence of what was said, but it was something like the following.

The first line of defence is that parliament can pass laws against the wishes of a prime minister. This happened in April when, even though Theresa May had said she would ask for an extension to the Brexit timetable, the Cooper-Letwin act was passed to make absolutely sure that she did so.

The question is how to get such legislation started, if the government provides no legislation or motion of its own that could be amended, and if it refuses to allow an opposition day before the end of October.

The answer to that is an application for an emergency debate, under standing order 24. It would be unprecedented for the speaker to allow such a debate to be used to propose, and vote on, a motion to take control of the parliamentary timetable, but anyone who thinks John Bercow wouldn’t do it hasn’t been paying attention.

There will be howls of outrage from advocates of a no-deal Brexit, who will denounce Bercow as biased, but how could an impartial speaker justify blocking a majority in the Commons on such an important question?

There is no question that the opponents of a no-deal Brexit have the numbers. True, the Cooper-Letwin act was passed by just one vote (it would have been two except that Emily Thornberry, the shadow foreign secretary, had a family emergency). But there are at least 12 current ministers who strongly oppose a no-deal Brexit and who, like Hammond, expect to be out of government when Johnson takes over.

Having taken control of parliamentary business for a day, the opponents of a no-deal Brexit need to pass two laws: one to prevent prime minister Johnson suspending parliament, and another to require him to seek a Brexit extension in the event that a deal isn't approved by 31 October. (The first objective might be achieved by Dominic Grieve, Tory former attorney general, with an amendment to a Northern Ireland bill on Monday.)

So I think Johnson will find his path to a no-deal exit obstructed by the time he goes to the EU summit on 17 October.

However, a law requiring a prime minister to “seek” an extension is not watertight. It cannot mandate him to accept whatever terms the EU might offer. Johnson might shrug and say he was unable to agree. That is why the Hammond Plan has to have a fallback – one that could be activated in the 13 days before the deadline of the end of October.

This is the nuclear option of bringing the government down. It will be harder to muster a majority for a vote of no confidence in Johnson’s government, but I think there are enough Tory MPs who see no future for themselves in politics and who think a no-deal Brexit would be so damaging that they have to stop it – “do or die”, you might say.

It doesn’t have to lead to a general election straight away – which might have been a deterrent for some MPs. If the opposition parties and Tory rebels can agree on a person to take over as a temporary prime minister, then Kenneth Clarke, for example, could do so for the sole purpose of agreeing an extension.

That would be peculiar, and I don’t think it would come to that: the threat would be sufficient to persuade Johnson to agree an extension himself.

It is possible, of course, that Johnson will agree some minor changes to Theresa May’s deal within nine weeks of becoming prime minister and secure the approval of the Commons for them, but it is hard to see where those extra votes would come from.

That’s why I think Johnson will win the leadership by a landslide, and then, as prime minister, collide with reality with – for him – disastrous results.