Boris Johnson will be remembered for killing the Belfast Agreement by bringing in a border in the Irish Sea

London and Dublin continue to claim that the ‘Good Friday’ Agreement is essential to the delivery of stability, good governance and reconciliation here.

Twenty four years’ experience show otherwise. The powersharing Executive has operated irregularly and for just over half of those years.

Some of its ministers have misused public funding to justify terrorist violence, flouted their own laws, and reportedly engaged in corruption. I detect no positive achievements.

The agreement institutions might have limped on for a few more years. But Boris Johnson struck the killer blow when he signed up for the EU Protocol.

‘Getting Brexit done’ went down well with his party, but he sacrificed Northern Ireland. That is why he should resign.

His protocol demolished the agreement. It set aside the principle of consent to constitutional change, the integrity of the Union, cross-community consensus and the parity of the East/West dimension.

Thanks to his recklessness, Northern Ireland will not benefit from Brexit, but will be subject to EU laws, regulations and court rulings — over which we will have no say — on goods, customs, VAT and state subsidies.

Obsessively stringent checks on goods arriving from Britain are already limiting choice, increasing costs, and taking providers out of the market. Businesses here are switching to suppliers in the south. Matters will get worse when Britain’s unilateral extension of the ‘grace periods’ for supermarkets and medicines ends.

More importantly, the protocol has ‘subjugated’ the Act of Union of 1800, which required there to be no duties or restrictions on goods crossing the Irish Sea.

The DUP belatedly recognised the damage. Since the May election, Jeffrey Donaldson has declined to engage with the agreement institutions until the government has addressed these problems effectively.

In response, Johnson introduced draft legislation in June — the Northern Ireland Protocol Bill — which would empower (not require) ministers to disapply parts of the protocol. They could set up ‘green lanes’ for goods travelling to end destinations in Northern Ireland; permit businesses here to choose whether to follow UK or EU rules; ignore EU subsidy rules; and set aside EU provisions on VAT. The EU Court of Justice could lose its role in enforcing the protocol.

In principle, this could repair the damage. But the bill is unlikely to be enacted or implemented effectively because of the turmoil in the Conservative leadership and the array of forces ranged against it.

Johnson will not expend political capital on it and most of his likely successors (except Liz Truss and perhaps Ben Wallace) have no enthusiasm for it.

Europhile Tories will argue that the UK must not breach international law, even though the EU and Ireland have done so repeatedly.

If he survives, Johnson will use the bill to kick the can down the road. He or his successor might persuade the DUP to go into the Assembly before October, avoiding a second election and the risk of having to introduce direct rule.

But the DUP cannot do this in good faith. If they do, they will lose the trust of the unionist electorate. That would be unwise.

The TUV is building a credible alternative slate of candidates. Jim Allister does not need many more votes or transfers to win significantly more seats at the DUP’s expense.

Dr WB Smith, Co-editor, The Idea of the Union, Belfast