IT takes three Labour politicians to change a lightbulb.

One to fit the bulb, another to unscrew and grind it to dust under their boot, and a third to brief the press that lightbulb-crushing was their policy all along.

You get the sense that when it comes to Labour policy on indyref2, Jeremy Corbyn is listening to the wrong people. Namely, his embittered Scottish Labour colleagues. On the campaign trail this week he issued a series of contradictory statements about when a Labour government would allow Scotland a vote on independence.

“Not in the first term” changed to “not in the first two years” the following day. The First Minister quipped on Twitter that at this rate Corbyn would be calling for #indyref2020 by the end of the week.

For her part, Nicola Sturgeon has been clear about what she would expect from a minority Labour government in return for the confidence and support of her MPs at Westminster.

You would expect Jeremy Corbyn to have given due consideration to her offer by now, not least because this week Professor John Curtice assessed the chance of a Labour majority in the upcoming election as “almost zero”.

Expectations of the Labour leader are low, but even his critics would expect him to be capable of maintaining a consistent position on indyref2 for the duration of an election campaign.

It is curious that so many Labour politicians seem aghast that the First Minister’s help is conditional on the people of Scotland having their say in another referendum.

That arrogance and entitlement is one of many reasons that Labour has fallen into such a sorry state in Scotland. If Jeremy Corbyn cannot convince the UK electorate to give him a working majority, he will have to compromise if he wants the privilege of becoming our next prime minister.

He doesn’t have a divine right to rule and neither does his party.

We saw this lack of self-awareness on display again this week when Corbyn posted a wildly misleading tweet about Nicola Sturgeon.

He wrote: “Nicola Sturgeon has just said this about me: ‘I won’t help him in power, to get into power, to stay in power.’ Just like in 1979, @theSNP are willing to usher in another heartless Conservative government.’’

In response, Channel 4 journalist Ciaran Jenkins said: “This quote retweeted over 2000 times is incomplete and ripped of context to the extent its meaning is changed.’’

Because what Nicola Sturgeon had actually said was that she wouldn’t help Corbyn into power “if he doesn’t accept the principle that whether there is a referendum in Scotland and what the timescale of that referendum should be, should be determined by the people of Scotland”.

The question we should be asking is: would Jeremy Corbyn really prefer another heartless Conservative government to the people of Scotland getting a vote on whether to become independent?

On balance, I suspect not. Which only makes his bluster this week even more infuriating.

“Back me, or you will be responsible for the Tory misery that follows” is a churlish, deeply unserious approach to politics.

I wonder how Labour supporters south of the Border feel as they watch their leader draw unnecessary red lines and make promises that he won’t be able to keep.

Imagine the fury from Labour voters if – on the cusp of a victory – Corbyn goes in a petulant strop and chases after defeat rather than negotiate with the SNP.

It is often said that Jeremy Corbyn doesn’t understand Scottish politics. But that isn’t the sin. The real outrage is that he has made such little effort since becoming leader to do so.

Watching his interviews with Scottish journalists this week, as he monotoned his way through his latest tired line on the Scottish constitutional question, he looked bored and disinterested.

With Labour trailing in the polls in Scotland and the prospect of many Scottish Labour MPs losing their seats, perhaps Corbyn is resigned to his party’s fate and sees little point in trying to win back support.

But if – as predicted – the SNP win the election in Scotland and become kingmakers, then Corbyn would do well to start paying attention to the mood of both his own supporters and voters in Scotland.

If he gets into Number 10 on the back of an SNP victory in Scotland, he can’t expect to ignore the manifesto on which the party won support.

In pledging to hold EUref2 within six months of Labour coming to power, Jeremy Corbyn has shown he understands how a mandate from the people is won and implemented.

In the coming weeks, he should extend that understanding to the people of Scotland. They have the right to choose a party and manifesto that best represents their interests.

If Scotland truly is an equal and valued member of the Union, then it’s high time Westminster politicians started treating it as such.