Is this the real reason Lord Frost resigned?

In his resignation letter, the Brexit minister Lord Frost justified his decision to quit by pointing to tax rises and Covid restrictions. But there is another potential reason given the timing. Late last week, the UK conceded that the European Court of Justice could have the final say over the Brexit settlement in Northern Ireland.

Frost is a negotiator. It might be that he didn't want to undermine his successor by over-emphasising the scale of the British retreat. Or it could be that he is holding back dissatisfaction with the negotiations for a second broadside at the Prime Minister.

But it is a critical development. ECJ oversight was always a red line for Brexiteers. Sovereignty demands that the final arbiter of British law resides in the United Kingdom. Where there must be an external mechanism due to an international agreement, there should be an impartial forum that treats both parties equally.

Having an EU institution police disputes between London and Brussels, which the EU wants, would be like having the Supreme Court as the final court of appeal for treaty disputes between the UK and the Republic of Ireland. They might be fine judges; Dublin would still be rightly furious at the suggestion.

Yet that is where things currently stand. Under the new proposals apparently floated by London, the ECJ would only be asked for its views if a politically-negotiated solution couldn't be found in the first instance. But given that this is Northern Ireland, and one side actively wants to undermine British sovereignty, the odds of regularly finding such political solutions seem very slim indeed.

Whether Frost speaks out or not, this speaks to a deeper political problem for the government. Frost could only ever be as muscular as Johnson was prepared to allow him. Thus, over the past couple of months, we have gone from a very robust line about triggering Article 16 — the mechanism that allows either side to suspend the Protocol — to the most recent news that actually, maybe the government’s red line about the jurisdiction of the ECJ wasn’t quite so red after all.

According to Dominic Cummings, Frost and his team did have a proper strategy for invoking Article 16 and using it to secure the reforms required to safeguard the integrity of the British state. But they knew the government didn’t have the bottle for it. And following the departure of most of the rest of the Prime Minister’s original Vote Leave team, they were also isolated within government.

Even accepting that Cummings has an axe to grind, that seems perfectly plausible. Johnson’s overall approach to the Union has been wildly erratic. One might plausibly favour either a more conciliatory ‘four nations’ strategy or a more muscular approach to unionism. The government has instead lurched haphazardly between the two.

It’s the same story on pretty much every important area where the Tories should be pursuing structural change. Ambitious planning reform has been abandoned. Detailed proposals for reforming the courts have been sidelined in favour of disinterring David Cameron’s ‘British Bill of Rights’. I couldn’t even tell you if this ministry has an education reform policy.

Time and again, Johnson has proven that his ‘fight or flight’ instinct is stuck on ‘flight’. He’s a talented campaigner with an uncommon knack for connecting with voters, at least until recently. But he isn’t going to fight to the last for the things he believes in because neither fighting nor believing things are major parts of his political character.

Now Liz Truss has to try and pick up where Frost left off, securing the changes Britain needs while avoiding the many pitfalls that await an unprepared English politician in Ulster. It will give Unionist MPs, who may sooner rather than later have to choose Johnson's successor, an opportunity to see what sort of metal this self-conscious heir to the Iron Lady is really made of.