Is Boris Johnson really willing to tear up his Brexit deal?

Boris Johnson is used to making threats about Brexit. It’s been a successful tactic for him ever since he pounced on the chance to replace Theresa May as prime minister when she failed to get her deal through parliament.

The opportunist emerged triumphant from a Tory leadership contest by offering a simple promise to get Brexit done, “do or die”, telling everyone he was willing to walk away with “no deal” if it meant pulling the UK out of the EU quickly.

We are almost three years into Johnson’s time at No 10. He is now threatening to undo the withdrawal deal he “got done” with Brussels in 2019.

The prime minister is happily staging yet another high-stakes game of chicken over Brexit, warning that his ministers could ditch the Northern Ireland protocol unilaterally.

Is he serious? It certainly looks that way. Foreign secretary Liz Truss is pushing hard for the plan to introduce radical legislation that would scrap protocol checks without the EU Commission’s consent, a move that has support in No 10.

EU officials are certainly taking it seriously, bracing themselves for action after months of vague rhetoric about triggering Article 16.

The European Commission is “likely” to move to suspend the Trade and Cooperation Agreement (TCA) with the UK if Downing Street takes the plunge by overriding the protocol, a Brussels source has told Bloomberg.

So it looks like we could be on course for a trade war – something British business groups have warned would have a “horrific” impact on food prices and the wider economy.

Not to mention the damage such a move would cause to the UK’s reputation for upholding international treaties, something May pointed out in parliament this week.

So why would he do it? Why would the prime minister be prepared to push the country into more economic trouble when the cost of living crisis is set to get worse?

Well, Johnson remains in serious trouble over Partygate.

More police fines are a possibility, and the full Sue Gray report is still to come – all as the PM watches the Tories’ poll numbers stagnate and wonders whether his backbenchers will finally move against him ahead of the next party conference.

Johnson and his Downing Street team appear to have calculated that Brexit rows are a good thing, politically speaking.

The economic concerns of chancellor Rishi Sunak and the Treasury are believed to have held sway over No 10 when Lord Frost was pushing for the move to suspend checks by triggering Article 16 at the end of last year.

But the chancellor is now a diminished force in cabinet, and the prime minister’s political desperation has changed the risk calculus.

Johnson will be hoping that a really big, nasty row with Brussels – one that may start with legal action but end with tariffs being slapped on goods – will keep a bloc of Brexiteer Tory MPs onside when the going gets rough in the months ahead.

It may even, if he’s very lucky, distract quite a few Brexit-backing voters, making them forget the law-breaking parties and focus instead on their favourite enemy: the EU.

Cynical? Yes, absolutely. But Johnson has a history of turning to ugly, us-and-them politics if it’s in his own immediate interest, regardless of the long-term consequences for the rest of us.