At what cost? UK PM Sunak to win post-Brexit trade vote in parliament

British Prime Minister Rishi Sunak is set to win parliamentary approval on Wednesday for a key element of a post-Brexit deal on Northern Ireland, a victory tainted by a lack of support from the province's biggest unionist party and some of his lawmakers.

Sunak has sought to end years of wrangling over Brexit by revisiting one of the trickiest parts of the negotiations - to ensure smooth trade to Northern Ireland without creating a so-called hard border with Britain or the European Union.

He agreed with the EU to introduce the "Stormont brake", aimed at offering Northern Ireland more control over whether to accept any new EU laws, as part of the so-called Windsor Framework of measures to soothe post-Brexit tensions.

But in Wednesday's vote in the lower house of parliament, those he most wanted to win over - Northern Ireland's Democratic Unionist Party (DUP), some Conservative Eurosceptic in the European Research Group (ERG) and his two predecessors, Boris Johnson and Liz Truss - are set to rebel.

Despite the opposition, Sunak is expected to win the vote - the rebellion is likely to be contained to still give the Conservatives a majority and if not, the opposition Labor Party says it will back the government.

Sunak's spokesperson has urged lawmakers to support the Stormont brake.

"(It) fundamentally restores or deals with the democratic deficit that existed," the spokesperson said.

The brake enables Britain to prevent new EU laws applying to goods in Northern Ireland if asked to do so by a third of lawmakers in the province's devolved legislature.

The ERG has described the measure as "practically useless" and the DUP has complained that it does not apply to existing EU law.

Sunak hailed securing the deal last month as a "decisive breakthrough", one which would ease post-Brexit trade between Britain and Northern Ireland, firmly root the province's place in the United Kingdom and give lawmakers there a say in whether they must implement EU law.
But the DUP has said the new deal does little to ease its concerns over the post-Brexit trading arrangements, saying the "brake does not deal with the fundamental issue which is the imposition of EU law".

The Northern Irish party, at odds with opinion polls suggesting 45% of voters in the province support the framework versus 17% opposed, has said it will keep talking to the government to try to assuage its concerns.

The DUP has for a year boycotted Northern Ireland's power-sharing government and has said it will not return to it until the post-Brexit trade arrangements are overhauled.

After the ERG published a legal document rubbishing most of the measures contained in the Windsor Framework, former prime minister Johnson, the face of the campaign to leave the EU, and his successor, Truss, said they would vote against the brake.

Johnson doubled down on his view that Sunak should stick to his policy of standing by legislation which would tear apart the current deal with the EU.

"The proposed arrangements would mean either that Northern Ireland remained captured by the EU legal order … or they would mean that the whole of the UK was unable properly to diverge and take advantage of Brexit," he said.