There are times in politics when a principled abstention is the right thing to do. It was the right action for Labour this week on Boris Johnson’s latest coronavirus restrictions. It will be the right thing to do, if it comes to a vote on a Johnson Brexit deal.

Sir Keir Starmer has not put a foot wrong since becoming Labour leader. Whipping Labour MPs to vote for a Johnson Brexit deal would be his first mistake.

We already know that any deal struck will be the hardest of Brexits. Long after Covid-19 is behind us, we will be living with the damaging consequences of a Tory Brexit deal for years — well up to and beyond the next election. Why would we, as a pro-European, internationalist party, aspiring to be the next government, want to give such a miserable outcome our endorsement?

None of the arguments I have heard in favour of Labour voting for a Johnson deal is persuasive.

Firstly, that it will “achieve closure” on Brexit. It won’t. Everyone accepts Brexit has happened. That is a fact. But the idea that the nature of our future relationship with Europe is going to be politically uncontested between Labour and the Tories, once the full impact of a hard Brexit begins to be felt after January 1, is fantasy.

Secondly, that it would help us win back the so-called “red wall” seats. This is to fight the last battle, rather than the next one and where we will be at the next election. It buys into the false Tory and Lexiteer narrative of why we lost so badly a year ago. The fact that good former colleagues, like Anna Turley, Phil Wilson and Mary Creagh, who lost their seats a year ago, are so dismayed at the idea of voting for a Johnson deal should make us pause. No voter, particularly in those areas that will be worst hit by a hard Brexit, is going to be more likely to vote Labour in 2024 because we voted for a damaging Brexit deal four years previously.

Thirdly, that we have to vote for Johnson’s deal, because we are against no deal. This is nonsense. If there is a deal, it will go through the Commons, unless we vote against it, which nobody is suggesting. It will not need Labour support.

Fourthly, that voting for a Johnson deal, won’t stop us criticising it. That’s true. We could vote for it and spend the next four years attacking it. But all you have to do is imagine yourself in the Today programme studio, or in the Commons, highlighting the latest factory closures, business relocations abroad, farmers going bust, price rises and border queues. The first thing our political opponents or any interviewer is going to say and repeat is: “But you voted for this.” The Lib Dems, SNP and Greens would have a field day.

Fifthly, that abstaining is wishy-washy and voting for it would look “decisive.” Yes, an abstention can take more effort to justify, but Sir Keir showed perfectly how that can be done when we abstained on the government’s latest tier system this week. We recognised the need for public health measures, but wanted to register our disapproval of the incompetence of the government. Speaking for myself and, I believe many colleagues, I would find it much easier to justify an abstention on a Johnson Brexit deal than a vote for it.

Sir Keir has already demonstrated admirable decisiveness in calling for an October circuit breaker and on dealing with antisemitism. Both of these have cut through successfully to the public. He doesn’t need to appear decisive on the wrong issue and in a way that could damage his authenticity, which the public and Labour members like.

I was one of the first MPs to nominate Sir Keir for the leadership. I spoke to several thousand party members for his campaign. Many existing ones, who had previously voted for Jeremy Corbyn, as well as the new members joining, were voting for Sir Keir because of his position on Europe. Given the still precarious power balance in the party and in many constituency Labour parties, these are people we need to keep. They will find it hard to understand whipping Labour MPs to support a Boris Johnson Brexit deal.