How seriously should we take Theresa May’s promise not to fight the 2022 election? The Prime Minister made the guarantee to Tory backbenchers yesterday, and my sense of the parliamentary party’s mood – and I’m told, that of the whips as well – was that she would not have won without making that pledge. She has restated it to the press today.

Of course, something that is still a subject of considerable bad feeling is that back in 2016, May promised nervous MPs in marginal constituencies that she, unlike several other candidates, wouldn’t risk their seats with an early election. Many of those MPs – Caroline Ansell, Neil Carmichael, Nicola Blackwood, James Berry to name just four – went on to lose their seats in 2017. This is a source of considerable bitterness among the friends and allies of the defeated.

We also know that May is happy to say things that are untrue, from the person she claimed could not be deported due to their pet cat to her continuing talk of an “implementation period” after 29 March 2019, when it is no such thing.

These are the concerns of MPs, including many who concluded that, for all they feared that May would stick around, a leadership election at this stage of the Brexit process was a risk they couldn’t afford.

It’s safe to say that if this parliament goes the full length then May won’t fight the 2022 election, not least because the Conservative parliamentary party will have plenty of opportunities to ensure that doesn’t happen. Whether it is a promise she intends to keep is neither here nor there: as far as May’s career goes, her pledge not to lead the Conservatives into the 2022 election is a lot like me pledging not to open the first ever hotel on Mars: it is not really something that is within my control.

But equally, it’s not in May’s control whether there is an election before 2022, or even within her year of immunity to challenge. It’s easy to see how the government could lose a vote of confidence if it becomes clear that it has no way of resolving the Brexit crisis, or if it successfully passes a withdrawal agreement – which come what may will include some type of backstop which will be unacceptable to the DUP. And then, of course, May is not going to resign as leader, because there isn’t time to replace her within the provisions of the Fixed-Term Parliaments Act. It could well be that, despite her public promise, May does end up leading the Conservatives into at least one more election.

So May has made a very odd promise, because it is not in her gift to decide if she fights the 2022 election anyway – and if there is an unexpected election she will have to fight it regardless.