A video grab from footage broadcast by the UK Parliament's Parliamentary Recording Unit (PRU) shows Britain's Foreign Secretary Boris Johnson (2R) listen as Britain's Prime Minister Theresa May speaks during the weekly Prime Minister's Questions (PMQs) session in the House of Commons in London on May 9, 2018. - RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT " AFP PHOTO / PRU " - NO USE FOR ENTERTAINMENT, SATIRICAL, MARKETING OR ADVERTISING CAMPAIGNS / AFP / PRU / HO / RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT " AFP PHOTO / PRU " - NO USE FOR ENTERTAINMENT, SATIRICAL, MARKETING OR ADVERTISING CAMPAIGNS Image Credit: AFP

It’s common to see Conservative prime ministers in torment over Europe, struggling weakly to arrive at an agreement with insurrectionary cabinet ministers. Even so, the public declaration by the Foreign Secretary, Boris Johnson, that Prime Minister Theresa May’s proposal for a customs “partnership” with Europe is “crazy” is without precedent. John Major’s life as prime minister was made a nightmare by the Eurosceptic rebels in his party. Another former prime minister David Cameron offered, and lost, a referendum on Britain’s EU membership that finished him off.

But throughout, Major and Cameron worked with loyal foreign secretaries who stuck with them in their contorted expediency. Johnson does the opposite: He publicly moves away from May.

Because it is Johnson who has launched the public onslaught, a thousand theories erupt as to his motive. Is he seeking to outperform even Jacob Rees-Mogg in the language deployed to rubbish May’s proposal for a post-Brexit trading relationship? Is this largely about Johnson’s leadership ambitions? Does he really mean it?

The answer to the first two questions is that any political figure who aches to be a leader will make calculations that are multilayered when the current leader is fragile. If Johnson still yearns for the crown after his traumatic withdrawal from the 2016 leadership contest, then his ambitions will certainly play a part in every utterance and move. But the answer to the third question, about whether or not he means what he says, applies more to his leadership calculation than to the actual substance of his intervention. It is irrelevant whether he genuinely regards the proposition for a post-Brexit customs arrangement as “crazy”, or believes it would “create a whole new web of bureaucracy” while denying Britain control over its own trade policy. I am sure he does think all of that, but it does not matter. He has given his verdict in public and is stuck with it.

The option of creating a new customs “partnership” where British officials would collect tariffs for the EU was passionately defended by the business secretary, Greg Clark, in an interview with the BBC on Monday. But it is now officially “crazy” as far as the foreign secretary is concerned. For the first time since May became prime minister, a Cabinet split on Brexit is out in the open. That is why Johnson’s intervention is of seismic significance. There has been much justifiable speculation about whether May could get a Brexit deal through the UK parliament. Now it is not at all clear that she can even get one through her Cabinet.

Johnson has spoken aloud, but his views are shared by other senior ministers, as we know from last week’s inconclusive Brexit Cabinet Committee. After that meeting, May sent her increasingly exasperated Brexit adviser, Olly Robbins, to see what changes he could make before yet another meeting. Robbins will be the biggest titan in the history of British diplomacy if he comes back from Brussels with a proposed agreement so different and yet so similar to the one that preceded it that the entire cabinet can unite around a revised policy.

On one level, the situation is beyond belief. The cabinet cannot agree on what it wants in relation to future trade arrangements when a deal with the rest of the European Union (EU) must be secured within months. In a rational world, ministers would have agreed on such matters before May triggered Article 50, more than a year ago. But in our current world the assertion is pointless. The reason May did not seek Cabinet consensus on any detail before now is that she knew the Cabinet would not agree. Instead, she followed the only other course available to her, which was to waffle in a way that reassured most in her party, but with words that were close to meaningless.

Even in her first big speech on Brexit, in January last year, she implied some relationship with the Customs Union without specifying the form. She spoke then of “associate membership”. I am an associate member of a tennis club. I have never known what it meant except that it is almost impossible to play tennis at that club.

The evasive terms chosen by May have kept the show on the road. And such imprecise language was similarly deployed in the phase one deal that was agreed at the end of last year. The ubiquitous term “alignment” was open to as many interpretations as the behaviour of Johnson. But waffling for ever was never an option. Now the time has arrived for real, meaningful detail, and cabinet unity is shattered.

At some point in the coming days, there will have to be resolution. If Johnson and his ministerial allies prevail while May and her allies concede, the nightmarish sequence for the prime minister will have only begun. She will at some point face a vote in the Commons on the customs union. Again the vote will be postponed for as long as possible, but cannot be avoided altogether. A majority of MPs believe, with good cause, that the government’s alternative proposal to address the need for frictionless trade and avoid a hard border in Ireland by means of technology is fantasy. She also has to get agreement with the rest of the EU, arguably an even bigger mountain to climb than managing her party.

May’s hope is that any successor would lead in the same weak context. A new prime minister would change neither the composition of the hung parliament nor the approach of the EU in the final negotiation. The unyielding obstacles and internal divisions block the path of any prime minister. At this late stage, there is no clear path towards Brexit — but May is likely to remain the Prime Minister doomed to seek one.

— Guardian News & Media Ltd

Steve Richards is political columnist and broadcaster.