Britain will detail Tuesday how it plans to overhaul post-Brexit trade rules in Northern Ireland which have sparked a political crisis in the province, amid fears it is risking a UK-EU trade war.

Foreign Secretary Liz Truss will “set out the rationale for our approach” in a statement to MPs in parliament, according to Prime Minister Boris Johnson’s spokesman.

The UK government is yet to confirm what that entails, but media reports have said it is planning legislation allowing London to unilaterally override some of the rules around Northern Irish trade.

London wants to rewrite the so-called Northern Ireland protocol, which it agreed as part of its 2019 divorce deal with the European Union, amid trading frictions since it came into force last year.

The arrangements, which mandate checks on goods arriving into Northern Ireland from England, Scotland and Wales, have angered the province’s unionists who claim they undermine its place within the UK.

Secretary of State for Northern Ireland Brandon Lewis said Tuesday that the protocol “doesn’t work for business, it doesn’t work for anybody in Northern Ireland”.

He told Sky News that problems should be solved “preferably by agreement with the European Union” but “we will do what we need to do to ensure that products can move to Northern Ireland in the way they should be able to… from Great Britain as part of the United Kingdom’s internal market.”

The largest pro-British party, the Democratic Unionist Party (DUP), is currently refusing to resume power-sharing in Belfast with pro-Irish rivals Sinn Fein until the protocol is reworked.

Its stance comes nearly two weeks after Sinn Fein won a historic first victory in elections for the devolved Stormont assembly, which entitle the party to the role of first minister in a joint executive with the DUP.

– ‘Legislative solution’ –

The impasse threatens to leave Northern Ireland, which suffered three decades of sectarian conflict until a 1998 accord largely ended the violence, without a government.

Johnson is adamant the current situation risks peace and stability in Northern Ireland and that his government has the right to act if the EU refuses to meet its demands.

“We don’t want to scrap it, but we think it can be fixed,” he told reporters during a visit Monday to Northern Ireland to meet its political leaders.

Reports say the mooted draft law, which will allow UK ministers to selectively disapply parts of the protocol, may not be tabled yet and would in any case take months to progress through parliament.

That could prove insufficient to persuade unionists to resume power-sharing in Northern Ireland, with the DUP saying Monday it needed “decisive action” not “the tabling of legislation”.

– ‘Keep their word’ –

The EU, which has been in discussions for months with the UK over improving the implementation of the protocol, has insisted it cannot be renegotiated.

European leaders have warned London against taking unilateral steps, and suggested it could jeopardise their entire Brexit deal, resulting in punitive tariffs and an effective trade war.

“This is an international treaty, it’s international law, we can’t just pretend it doesn’t exist,” Ireland’s Foreign Minister Simon Coveney said Monday in Brussels.

Johnson’s government says that checks on goods heading to Northern Ireland from England, Scotland and Wales are undermining peace in the province, with unionist protests already turning violent in the past 18 months.

The separate trading arrangements, which bind the province to many European rules, were agreed because it has the UK’s only land border with the EU.

Keeping the border open with neighbouring Ireland, an EU member, was mandated in the Good Friday Agreement, given the frontier was a frequent flashpoint for violence.

But it means checks have to be done elsewhere, to prevent goods getting into the EU single market and customs union by the back door via Northern Ireland.

The United States, which was a guarantor of the Good Friday Agreement, has expressed alarm at suggestions the UK could scrap the protocol.