The Tories are sacrificing Northern Irish businesses on the altar of Brexit purity | Polly Toynbee

Single-market status has been a boon to firms - but stirring up a trade dispute with the EU may be worth more to Boris Johnson

Here comes the destroyer, as David Frost, the Brexit minister, stomps into talks on the Northern Ireland protocol this week with European commission vice-president Maro efovi. His mission from Boris Johnson is to stir up Brexit trouble, and keep stirring: yes, even at the risk of stirring the darkest shadows of Northern Ireland's history. Let Brexit never be done if it can keep alive the antagonisms that shot Johnson into No 10.

Johnson may miscalculate the public's appetite for new Eurostrife: Get Brexit done" worked with many voters who never wanted to hear the word again. But he may be hoping that EU trade wars against the despots of Brussels can distract voters from his pile-up of crises: shortages of HGV drivers and butchers, port blockages, NHS and social care at tipping point, music and arts crippled for lack of EU visas, soaring energy bills. EU noise might help drown out some of the bad news from next week's austerity budget.

Polly Toynbee is a Guardian columnist