Jeremy Corbyn has presented MPs with the challenge of our times – if they can’t meet it, Britain’s outlook is bleak

At a moment of national emergency it is heartening that Jeremy Corbyn, whatever his previous equivocations, has committed himself not only to stopping a no-deal Brexit, but also to finding the means to do so with others.

Writing for The Independent, the Labour leader indicates that he will support the most immediate, most practical and obvious way to avert catastrophe and restore democratic accountability to the Brexit process.

As has been demonstrated on numerous occasions, there is no majority in this House of Commons for a no-deal Brexit. The terms of the 2016 referendum do not amount to a necessary mandate for a no-deal Brexit. There should not therefore be any no-deal Brexit without democratic approval, either through a Commons vote or a Final Say national referendum, and preferably both. It is not a matter of “stopping Brexit” or even stopping a no-deal Brexit as such: it is simply to ensure that if the UK is to leave without a deal, without a transition period, with tariffs and barriers to trade and travel, and with long term economic and constitutional damage, then all those things must be positively willed and approved by the people and their representatives.

It bears repeating that if a no-deal Brexit is what the British people do actually want, then no one can nor should stop it. But the 2016 referendum result did not give sufficient authority to such a move.

The numbers exist in parliament to deliver a law preventing no deal if MPs are well organised enough to take back control, to forbid crashing out without prior parliamentary approval, and amend the Article 50 and other legislation accordingly.

We know this can be done because something very similar was achieved in the spring and again in the summer. It is true that the current administration shows a much more ruthless disregard for the rights of parliament even than its predecessor; a law preventing no deal will be trickier to achieve, but there is a way.

Parliament is against no-deal Brexit by a substantial margin – now it needs to voice its resistance through law.

That done, then the anti no-deal parties, and various dissident groups and independents, can return to their arguments about an emergency government and other future moves such as a Final Say referendum or general election.

The Johnson government may be allowed to continue if it accepts as it must the will of parliament, or it can take its case to the people, which is the whole point of the exercise. So, far from bringing a Conservative government down, Tory dissenters will be allowing it to continue in office with the proper consent of parliament – a vote of no confidence is not the only way to stop no-deal.

Indeed, as has been spun in the media, Mr Johnson might table his own motion of no confidence and deliberately lose it so as to call a snap election. It is a weapon that can be used, and can backfire, for either side. Yet the anti no-deal law will remain in force unless he can find a majority to abolish it. That again is the democratic way, and legitimate politics.

It is also worth bearing in mind that all but two of the Conservative leadership contenders opposed a no-deal Brexit without parliamentary assent – Mr Johnson and Dominic Raab being willing to suspend parliament to push it through. Ignoring the Commons is not a popular idea even in Tory ranks. Amendments to a law on Northern Ireland now make that impossible, in any case, so the dissolution and general election gambit is the only one left to the cabinet. It is full of dangers: no deal should be stopped before we ever get near that being a realistic scenario.

For what it is worth, Mr Corbyn has precedent on his side when arguing that as leader of the opposition he has the right to try to form an alternative government if Mr Johnson loses a vote of confidence. However, this argument does not necessarily reflect political reality. The last time such a situation arose was after the 2010 general election, also a hung parliament. Then, Gordon Brown, still prime minister but the leader of the second-largest Commons party, offered to stand aside as prime minister after a new Labour leader was elected to facilitate a Labour-Liberal Democrat rainbow coalition. That time it was not enough to persuade the Lib Dems; this time, of course, it would be.

It seems common sense now that for so many parties, groups and independents to work together they need a consensus on who will lead them, and what their aim should be. The second of those questions is vastly more important than the first, and Jo Swinson should not fetishise the first by opposing Mr Corbyn in all circumstances. If he agrees with her policies on Brexit, that should be good enough. She, too, needs to put country before party.

In the meantime, they have a more pressing task, but a more achievable one. With calm determination and faith in the depth of their support and democratic legitimacy, a majority of MPs may find it surprisingly easy to outlaw no-deal Brexit unless parliament approves it.

That is work enough for them to accomplish for now. If they cannot even agree on that, then the outlook for Britain is bleak indeed.