When you think about it, the Brexiteers' threats to quit over the customs union make very little sense – even for them

You might think they’d be better off with some kind of fudge like the ‘customs partnership’ currently being mooted, but this is an issue on which cold calculation may not be possible

Boris Johnson, Liam Fox and David Davis have been kicking up a stink about the possibility of a ‘customs arrangement’ (PA)

Distraction and bribery are, as every parent knows, the best ways of dealing with distraught children. Theresa May needs another Russian spy drama and to hand out some Conservative Party vice chairpersonships to calm down her restive MPs.

Instead, she will be chairing a renewed outbreak of the squabbling at the cabinet’s Brexit committee this afternoon.

The hard Brexiteers have not been reassured by Amber Rudd’s replacement on the committee by Sajid Javid. A punchy Remainer replaced by a crypto-Leaver shifts the tone at the top of government, but it does not change the arithmetic in the House of Commons.

The reason Boris Johnson, David Davis and Liam Fox are threatening to quit (again) is that they can count. They know that there is a majority in the House of Commons for Britain to stay in a customs union with the EU. There are more than 12 Tory soft Brexiteers prepared to vote against the government on this, which is enough to overturn May’s majority, even taking the handful of Labour hard Brexiteers into account.

What is worse for Johnson, Davis and Fox is that they fear that, if Theresa May decided to compromise on a customs union, there would be a majority to support her among Tory MPs.

That may be why some of Jacob Rees-Mogg’s group of Eurosceptic Tories are warning that the government could “collapse” if the prime minister tries to keep Britain in any kind of customs union. At the moment, they are concentrating their fire on May’s “customs partnership”, which is one of the options that will be discussed at this afternoon’s meeting.

It is not really a customs union, but the Eurosceptics fear it could be modified during the Brexit talks to become like one. Their supporters’ opposition to it is curious, because, if they kill it off, May will be left with the choice of no customs union (which they want) or a proper customs union (which has more support in the Commons).

You might think they’d be better off with some kind of fudge, but this is an issue on which cold calculation may not be possible. There may be a spasm of anti-EU emotion, which is why it is so dangerous for May. The Rees-Mogg faction shouldn’t try to trigger a leadership contest because they would probably lose. They need 48 names to start the process but then they need 159 votes to defeat May in a vote of confidence in her leadership.

But leadership contests tend to take on a life of their own and, although May should defeat her critics, nothing can be guaranteed. So who can blame her – after the last time she went into an election as a certain winner – for trying to bribe and distract her irrational MPs from triggering a contest?

That’s why this afternoon’s meeting is unlikely to come to any firm conclusions. Why should she provoke either side before she absolutely has to? Because time is running out to set up the customs arrangements for after the transition period? Well, according to Whitehall sources speaking to The Times, it is already too late for that.

Theresa May’s survival, week by week, seems to be more important. So don’t expect the customs union problem to be sorted out soon. The prime minister is hoping for a distraction or two to keep her trigger-happy backbenchers at bay while she delays the moment of decision until as late as possible.