When is the right time for Labour to call a vote of no confidence in the government? According to certain pro-Remain Labour MPs, it was Monday, after May pulled the vote of the Withdrawal Agreement.

No, claimed the leadership’s supporters—that would only serve to unite the Conservatives at a time when they are horrendously split.

This morning, as it emerged that Theresa May was facing a no confidence vote of a very different kind, the leadership appeared to be vindicated. Even some of those who had called for a no confidence vote now accept they were wrong.

But that still leaves the question of when a no confidence vote should be called. First, let’s look at the numbers. There are 315 Conservative MPs (plus two as-good-as Conservatives currently without the whip). Add in the 10 DUP MPs and the government has 327 MPs who would be expected to back it in a no confidence vote.

Opposing them are 257 Labour MPs (plus 5 who ran as Labour candidates but are now, for various reasons, without the whip), 35 from the SNP, 11 Lib Dems (plus one whipless MP), 4 from Plaid Cyrmu, a solitary Green, and Sylvia Hermon, an independent. All in all, that’s 315. (There are eight more MPs—the speaker and seven from Sinn Féin—who all, of course, do not vote.)

For the opposition to win a no confidence vote they need to persuade seven government supporters to switch sides. Is the DUP willing to support the Labour party—led by the Sinn Féin-supporting Jeremy Corbyn and John McDonnell—in its efforts to bring down the government? No.

Are there seven Conservative MPs willing to support the Labour party in its efforts to bring down the government? At the moment, no.

This could all change depending on what happens tonight. Were May to lose and be replaced by a hardline Brexiteer who wants the country to leave without a deal, some of those pro-European Conservative MPs may be willing to back a no confidence motion—but even that is an extremely long shot.

Do they want to win?

But none of this matters if the point of holding a no confidence vote isn’t in order to bring down the government. And that, strangely, is the position of the vote’s loudest proponents: Remain supporters.

Does Nicola Sturgeon really want an election now? Of course not. The SNP could lose seats. Does Vince Cable want an election now? No, not really. The Liberal Democrats might hope to pick up a few more seats, but elections are expensive and the Lib Dems have very little money. Do People’s Vote-supporting Labour MPs like Chuka Umunna or Chris Leslie want an election now? Absolutely not. Neither is guaranteed to be the candidate—and neither would fancy going into an election backing Jeremy Corbyn. (Umunna, let’s not forget, recently claimed his party was “institutionally racist.”)

They don’t want an election; they want a referendum. And the only chance they have of getting referendum is if the Labour party back it.

Under Labour’s current Brexit policy, agreed after fraught closed-door debate at its party conference in October, the party will only give its support for a new referendum if there is no chance of a general election.

Were a no confidence vote to be held and lost, the Labour leadership would come under pressure to give its support to a referendum.

That’s something Corbyn and McDonnell want to avoid. For them, Brexit is a distraction. The real transformative change that Britain needs, they argue, is a Labour government—and whether the country is in or out of the European Union is while not irrelevant, certainly nowhere near as important as others tend to believe.

All of which leaves us in an odd position. Remain supporters want a no confidence vote they can lose, but will need the backing of Jeremy Corbyn who will only push for a vote he can win, which can only happen if he has the support of Tory MPs who don’t want him to become prime minister. You should have no confidence that a no confidence vote will ever take place.