Theresa May’s customs nightmare continues. The Prime Minister has issued a plea to her warring cabinet in today’s Sunday Times, urging them to trust her to deliver the Brexit they want.

But no matter how enthusiastically May adopts the language of the Brexiteers – repeatedly promising to "take back control” in today's piece – any hope of resolving the impasse over Britain’s future customs relationship with the EU remains forlorn.

Speaking on the Andrew Marr Show this morning, Michael Gove, who has been assigned to the working group examining May’s favoured customs partnership but instead backs the technology-based "maximum facilitation" (max fac) option, dampened hopes of the Brexiteers ceding ground.

Though – in the intended spirit of May’s working group exercise – Gove said neither customs model was perfect, the Environment Secretary essentially went on to repeat Boris Johnson’s “crazy” criticism of May’s proposal, albeit with more temperate language.

“Because it’s novel, because no model like this exists, there have to be significant question marks over the deliverability of it on time,” he said. “More than that, what the new customs partnership requires the British government to do is in effect act the tax collector and very possible the effective deliverer of regulation for the European Union.

“It’s my view that the new customs partnership has flaws and that they need to be tested.”

In the view of Gove and other senior Brexiteers, however, the model has already failed the tests set out by the Prime Minister: namely, taking back control of laws and borders.

The Environment Secretary's words reflect how some Leavers view the working groups: a means by which to politely put the customs partnership out of its misery and rubber-stamp "max fac" as government policy. But should they do so, any consensus would prove fragile once it left Westminster and was presented to the EU27.

Also speaking on the Marr Show, Simon Coveney, the Irish Foreign Minister, said Dublin expected May to “follow through on” her commitment to maintaining an open border, without any physical infrastructure, on the island of Ireland (a promise restated by May in the Sunday Times).

“It would be helpful if the British government had some consensus around this concept, as opposed to consensus around something else that people seem to think might work using technology or some other way of creating as seamless a border as possible, but nevertheless border infrastructure,” Coveney said.

In dismissing max fac, Coveney has made it clear that any compromise that pleases the cabinet Brexiteers won’t satisfy the EU. Likewise, any compromise brokered between the EU and May – which Coveney indicated this morning isn’t out of the question – won’t satisfy the Brexiteers.

And should any solution prove an inadequate answer to the border issue, May would be expected to contravene another of the red lines she drew in her Sunday Times piece this morning.

The so-called backstop agreement on Northern Ireland would kick in, likely meaning that the self-described “proud Unionist” in Downing Street would have to accede to the differential solution for Northern Ireland she has pledged to avoid, or, even less palatably, stay in the customs union on a UK-wide basis.

The DUP has made clear what the former scenario would mean for its relationship with the government. The latter would be a near-impossible sell to most Brexiteers.

No matter how passionately it is sold to the doubters, May’s package of red lines and commitments remains an unworkable mess of internal contradictions. At least one party to the debate will have to be disappointed. It’s clear that the Prime Minister has yet to work out which.