Why are so many MPs calling on Jeremy Corbyn to bring forward a motion of no confidence in Theresa May’s leadership? More than 50 Labour MPs – all of them supporters of a second referendum – have called for the Leader of the Opposition to bring a motion of no confidence, joining Vince Cable, the leader of the Liberal Democrats, Nicola Sturgeon, the leader of the SNP, and the leaders of the Plaid Cymru and the Green parliamentary groups in urging Corbyn to do the same.

The Labour leadership has declined the opportunity, saying that they aren’t going to call a vote of no confidence until they think they have a passable chance of winning one, which they don’t as it stands. No Conservative MP has even hinted that they might be willing to vote against their government, while the stated position of the DUP is that until the government successfully passes a Brexit deal containing a backstop, they will continue to support the Conservatives in motions of no confidence.

Several high-level Labour officials have spoken as if they have only one shot at a confidence vote, and Jeremy Corbyn appeared to suggest that the terms of the Fixed Term Parliaments Act means that Labour can try just once every year. This is not the case: there is no limit to how many times you can try to bring down the government. During the last period of extended minority government, 1974-79, Margaret Thatcher tried to no confidence the government on at least three separate occasions: once following the loss of Jim Callaghan’s parliamentary majority, once during the Winter of Discontent and finally and successfully after the Labour government failed to secure Scottish devolution.

But it is also not really accurate to say that only Jeremy Corbyn can trigger a motion of no confidence in the government: in 1979, the final and successful attempt to force Labour out of office was initiated not by the Conservatives but the SNP. While only Labour, as the official opposition, are guaranteed a time and a vote, in practice, should Ian Blackford (the leader of the SNP in Parliament) or Vince Cable seek one they will get one.

Of course, it does not matter because whatever happens, under whatever circumstances, the Labour Party, the SNP, the Liberal Democrats, Plaid Cymru and Caroline Lucas will all certainly vote against the Conservatives in any motion of confidence. The reason why one won’t succeed is that the DUP are not, as it stands, inclined to back one.

So what’s going on? It comes down to Labour’s Brexit policy, the fraught compromise hammered out at that party’s conference. Labour’s position is to first attempt to trigger a new election so they can negotiate Brexit and if that fails to support another referendum on the United Kingdom’s membership of the European Union.

The open question as far as Labour is concerned is where the emphasis is. Does it mean “Look, realistically, the Fixed Term Parliaments Act being what it is, we are never going to get an election this side of a Brexit deal passing, so let’s just support another referendum?”. Does it mean, sincerely, “Let’s try for an election and if not, a second referendum?” or does it mean “Let’s do everything we can to look like we might commit to a second referendum while doing everything we can to avoid it”? Well, the answer is that it depends on who you talk to. All three opinions are represented within Corbyn’s inner circle. Opponents of a second referendum aren’t merely confirmed to Team Corbyn’s committed Brexiteers. Others just believe that another referendum cannot be won and that calling for one would sabotage the party’s hopes of winning the next election.

One thing that the various parliamentary factions all agree on is that the closer we get to 29 March 2019 – the date that the United Kingdom will leave the European Union, whether it has reached a deal or not – everyone else is going to be more inclined to give them what they want. For the Labour leadership, that means that pro-European Conservatives may countenance voting with the Opposition parties in a vote of no confidence. For advocates of a close relationship with the European Union, that means that MPs may vote for an amended political declaration and for a withdrawal agreement that is functionally identical to the one on the table. For Theresa May, that means Parliament belatedly supporting her deal. And for supporters of another referendum, that means supporting a referendum on May’s agreement, with the option to call off the entire Brexit project and stay in the European Union.

So what’s really happening here is a bid accelerate the evolution of Labour’s position – for them to have tried for an election and for the second part of the party’s platform, the support for another referendum, to kick into gear. That’s why people are calling on Corbyn to trigger a confidence vote he cannot win. But the reason why Corbyn is, so far, declining to model his approach to confidence motions on Margaret Thatcher is that he is loathe to give up his flexibility on the Brexit issue.