The UK and EU will on Friday formally agree a post-Brexit deal to overhaul Northern Irish trade rules after lawmakers from both parties approved it despite a rebellion within Prime Minister Rishi Sunak's party.
UK foreign minister James Cleverly and EU Commission vice president Maros Sefcovic will sign off the "Windsor Framework" at a joint committee meeting in London.
UK lawmakers overwhelmingly endorsed a crucial part of the deal on Wednesday, in the face of a rebellion by ex-leader Boris Johnson and other hardline Conservative eurosceptics.
The vote on the framework's so-called "Stormont brake" -- which hands Northern Irish lawmakers an effective veto over new European Union rules being implemented in the UK province -- won the backing of 515 MPs, with 29 opposed.
"By formally approving the Windsor Framework, we are delivering on our commitment to provide stability and certainty for Northern Ireland," Cleverly said before Friday's meeting.
"The Framework is the best deal for Northern Ireland, safeguarding its place in the Union.
"I look forward to further effective cooperation with the EU on key issues, such as security and energy," he added.
Once formally agreed, the UK government said it will then begin the process of implementing the framework.
Despite Friday's show of unity, the new deal has reopened old divisions within Sunak's party.
Twenty-two Tory MPs -- including Johnson and fellow former leader Liz Truss -- opposed the brake in Wednesday's vote, while another 48 declined to vote.
MPs from Northern Ireland's largest pro-UK party, the Democratic Unionist Party (DUP), also voted against, suggesting that Sunak will struggle to get the party to resume power-sharing in Belfast.
The Stormont brake is a key cog in the new framework, which aims to reset strained ties between Britain and the bloc.
But it is also hoped the pact can pave the way for devolved government to restart in Northern Ireland, after the DUP collapsed the executive last year over its opposition to existing post-Brexit trade rules.
Northern Ireland is still in the European customs union and single market because of the need to keep an open border with EU member Ireland to the south as part of a 1998 peace deal.
With the rest of the UK out of the EU, that has caused headaches on how to protect the single market on goods heading across the Irish Sea and, unionists claim, made a united Ireland more likely.
DUP leader Jeffrey Donaldson said the framework failed to solve its concerns about Northern Ireland's ability to trade with the rest of the UK.
"That is the bottom line for us," he told MPs on Wednesday. "Until that is resolved, I can't commit to the government that we will restore the political institutions."
Brexit figurehead Johnson called the framework "not acceptable" as he opposed it.
He urged the government to stick with legislation he helped craft that would unilaterally disregard existing EU rules in Northern Ireland until Brussels agreed acceptable alternatives.
But that draft law, introduced last year, prompted the bloc to threaten reprisals and a damaging wider trade war, further souring relations.