Jeremy Corbyn must put the national interest first in stopping a no-deal Brexit

Jeremy Corbyn understands politics better than Jo Swinson does. The old leader of the Labour Party outwitted the new leader of the Liberal Democrats with his letter to opposition leaders this week. In it, he proposed that they should make him temporary prime minister charged with agreeing a further postponement of our departure from the European Union while a general election is held.

Ms Swinson responded to this invitation with the Meat Loaf caveat, as Sunder Katwala, the director of British Future, has named it. She will do anything to stop a no-deal Brexit, she declared, but she won’t do that.

This made her look churlish, especially when Nicola Sturgeon, leader of the Scottish National Party, Liz Saville Roberts, Plaid Cymru’s leader in Westminster, and even Guto Bebb, a Conservative opponent of no-deal Brexit, sounded positive about the plan. Ms Swinson admitted her error – in effect – when she later wrote to Mr Corbyn agreeing to discuss his plan with him.

This was the right response. Mr Corbyn, as leader of the opposition, is entitled to put himself forward as the first choice of alternative prime minister if the House of Commons should seek to depose Boris Johnson. The leaders of other opposition parties should allow him to make his case before they point out the flaws in his plan.

However, Ms Swinson is right that Mr Corbyn’s plan is deeply flawed. What this fall-back plan to prevent a no-deal Brexit needs is an explicitly temporary arrangement.

It needs to replace Mr Johnson with a caretaker prime minister given a tightly limited set of tasks. This person would be required to agree with EU leaders a new extension of the Article 50 deadline. They would need to occupy the office of prime minister during the five weeks of an election campaign, so preferably would have the experience needed to lead an interim government through any crises that might occur. After the election, a permanent prime minister would then be appointed.

The drawbacks of Mr Corbyn in such a role are obvious. As someone who seeks to be permanent prime minister, he would be expected to use a temporary post to press his advantage during the election. The best person for the role would be someone who was prepared to put party interests to one side.

More substantially, Mr Corbyn would fail to win the support of the largest possible number of MPs for what would be a complicated and unprecedented manoeuvre. The venture cannot succeed without the resolute support of between 10 and 20 Conservative MPs, who are already being asked to put country before party by bringing down a Conservative prime minister. Asking them to put someone they regard as a dangerous Marxist in No 10 is hardly calculated to maximise the chances of success.

Ms Swinson is right, therefore, that Kenneth Clarke or Harriet Harman would be more suitable candidates. Indeed, she claims to have sounded them out and that they would be willing to serve.

This brings us to the paradox of the scheme. All of its complex details have to be agreed in advance, or else MPs will be unwilling to vote to remove Mr Johnson on a motion of no confidence. Unless a temporary government is ready to go, bringing down Mr Johnson could lead to a general election with the timing in Mr Johnson’s power, and therefore to a possible no-deal exit during the election campaign.

But as soon as an alternative prime minister is agreed, and can demonstrate that they have the support of a majority in the Commons, Mr Johnson would probably seek to stay in office by asking the EU for an extension himself, and by asking parliament to hold an election. In such a contest he would no doubt present himself as the champion of the people, frustrated by “collaborators” in parliament.

In which case, Mr Corbyn would get the election he wants without having to cede anything to Mr Clarke or Ms Harman.

The key to stopping a no-deal Brexit, therefore, is to persuade Mr Corbyn to set aside – temporarily – his claim as alternative prime minister. He has to stand aside and deliver the greatest possible number of Labour MPs to a united front against a no-deal Brexit. The Labour leader has said he would use “all means necessary” to stop Britain leaving the EU without agreement. Mr Corbyn, above all, has to prove he means it.