Sinn Féin has said a united Ireland is “within touching distance” as the party prepares to claim the post of Northern Ireland first minister for the first time. Mary Lou McDonald said on Tuesday that the expected restoration of power sharing in the wake of a deal between the Democratic Unionist party and the UK government came amid a “historical turning of the wheel” that would unite the island. “In historic terms, it is within touching distance and I think that is a very exciting thing and I hope people will find that a very welcoming conversation,” the Sinn Féin leader said. According to a speedy political choreography that is supposed to unfold at Westminster on Wednesday and Thursday, her deputy, Michelle O’Neill, could become first minister of the Stormont executive by the weekend. “That will be a moment of very great significance, not simply because we haven’t had government for so long but because it will be the first time that we will have a Sinn Féin first minister, a nationalist first minister,” McDonald said. O’Neill became the region’s putative first minister when Sinn Féin overtook the DUP as the biggest party in the 2022 assembly election. But a DUP boycott to protest against post-Brexit trading arrangements mothballed Stormont. The DUP leader, Sir Jeffrey Donaldson, signalled an end to two years of deadlock early on Tuesday when a tumultuous meeting of the party’s 130-member executive endorsed a deal to revive power sharing. The deal will remove restrictions on the movement of goods within the UK, Donaldson said. “That was our core key objective and I believe what we have secured represents real change and everybody will be able to see it for themselves.” He has promised “zero checks, zero customs paperwork on goods moving within the United Kingdom”. The DUP endorsement is conditional on two statutory instruments at Westminster to give legislative effect to Downing Street commitments on trade and sovereignty. Chris Heaton-Harris, the UK’s Northern Ireland secretary, said the deal featured a “vast array of decent improvements” and would be published on Wednesday. The legislation is expected to be fast-tracked through Westminster on Thursday. A spokesperson for Rishi Sunak said the deal was a “strong basis” to restore Stormont. Downing Street said the prime minister had a “good call” with Leo Varadkar. Ireland’s taoiseach has welcomed the deal but he cautioned that Dublin and Brussels needed to see the text to be confident there were no “negative consequences” for the Windsor framework or for the Good Friday agreement. The European Commission echoed the guarded welcome. “We will examine those texts when the time comes,” said a spokesperson. Conservative MPs have expressed concern the deal could limit Great Britain’s ability to diverge from EU rules in the future to limit the impact of an Irish Sea border on internal trade with Northern Ireland. Downing Street said the deal would not prevent the UK from exploiting post-Brexit freedoms. If there are no glitches, Stormont could be recalled as early as Friday to elect an assembly speaker and appoint an executive drawn from Sinn Féin, the DUP, the Alliance party and the Ulster Unionist party. The DUP will be entitled to the deputy first minister post, which has equal power to first minister but less prestige and symbolic weight. O’Neill said Stormont faced an urgent workload, including a fiscal crisis, strikes and crumbling healthcare. “We have a lot of hard work ahead of us, a slog ahead of us, but collectively we can do better for the people we serve. Collectively, we can fight back against this Tory austerity agenda, collectively we can stand up and fight hard for public services.” The government has offered a £3.3bn financial package that is conditional on Stormont’s restoration. It includes funding for pay rises that could avert public sector strikes, though not a strike by transport workers that is to go ahead on Thursday. The Alliance leader, Naomi Long, said the breakthrough deal brought “bittersweet emotions” because of the time Stormont had been absent. Matthew O’Toole, of the Social Democratic and Labour party, said it was “not the time for champagne corks to pop or balloons to be released in celebration” given the failures of the past two years. Jim Allister, the leader of the hardline Traditional Unionist Voice, accused the DUP of a “tawdry climbdown” and said its boycott should continue.