When those bitter blood enemies, Ian Paisley and Martin McGuinness, finally agreed to share power amicably together in 2007, it was one of those “it’ll never happen” moments. The 2007 agreement I helped negotiate under Tony Blair ended a five-year suspension of the Northern Ireland assembly. So, too, was the 1998 Good Friday agreement, celebrating its 25th anniversary this year, which sealed the end of the Troubles – those terrible decades of terror and horror, the most recent and tragic manifestation of generations of violent inter-communal division in Northern Ireland. The Good Friday agreement resolved what seemed to be intractable problems: the release of prisoners who’d committed atrocities; changes to the Irish constitution; establishing a completely new, inclusive self-government – even when the IRA had still not decommissioned its arms. The key problems facing us in 2007 were the acceptance of devolved policing and the rule of law for Sinn Féin, and for the DUP, the acceptance of power sharing, impossibly difficult hurdles for those two largest parties with the peace process still in its infancy. Despite the challenges, the deal saw power-sharing operate more or less stably for 10 years, until it collapsed in 2017 following the crisis over the renewable energy payments scandal. Stormont was suspended for three years before being uneasily restored. Brexit provoked another collapse early last year, this time led by the DUP. It was objecting to a de facto border down the Irish Sea negotiated by Boris Johnson in his Brexit Northern Ireland protocol deal. A divide from the rest of the UK understandably upset unionists, especially with Johnson pretending he hadn’t even done it. Yet the people and politicians of Northern Ireland have bridged much greater divides at times when wounds were a lot more raw. Crucially, achieving agreement in 1998 and in 2007 required the UK government to stick to an “honest broker” role, and to work consensually with international partners, especially the US and the EU. Tragically – and at least until Rishi Sunak’s Windsor framework removed the extremely rough edges of the protocol – that has not happened under the Tories since 2010, when David Cameron formed a general election alliance with the Ulster Unionists and Theresa May was later sustained in power by the DUP. Johnson and Liz Truss then destroyed any remaining trust with Dublin, Brussels and Washington. Their “hard” Brexit redrew the jagged dividing lines in Northern Ireland that had been so elegantly smoothed by the Good Friday agreement and its successors. Questions around borders, identity, citizenship and self-determination, which had faded into the background, became once more all-consuming issues for a society also facing massive crises in public services and the cost of living. Despite Sunak being forced to drop the international law-breaking NI protocol bill, his government has not resiled from other plans that would throw still more Brexit-shaped spanners into the engine of Northern Ireland’s peace process. If passed unamended, the retained EU law bill will automatically scrap thousands of safety standards, environmental protections and rights that parliament voted to implement while the UK was an EU member. This could unleash economic chaos in Britain, and have an even worse impact in Northern Ireland, the only part of the UK to share a land border with the EU and remain within its single market. The government is also flirting with the idea of removing the UK from all or parts of the European convention on human rights (ECHR) in pursuit of its abhorrent Rwanda plan, shirking not only its obligations to refugees under international law, but also to the people of Northern Ireland. The Good Friday agreement is an international treaty, and the ECHR is directly referenced in its text, guaranteeing people in Northern Ireland protections under its terms. Any attempt to dilute the UK’s adherence to the ECHR would probably breach it, while removing the UK from it completely would put us in an unenviable club with Belarus as the only European countries not signatory to it. This willingness to inflict long-term damage for dog-whistle, short-term political advantage is reckless, endangering the Good Friday peace process and making it more difficult to restore Stormont. The government should be focused on removing the new Brexit-resurrected barriers inflaming old divisions, and by doing so help create a calmer context in Northern Ireland in which agreement can be reached. Much of the work has already been undertaken by my colleague Hilary Benn, who, through the UK Trade and Business Commission, continues to gather evidence on the negative impact of Brexit and new trade deals. The Good Friday agreement was a masterpiece of constructive ambiguity and pragmatic generosity, the result of focused and intensive negotiations; and its offspring, the 2007 deal, brought together the two parties that were nowhere near agreeing to share power in 1998. Time is needed without further headwinds from the Brexit bunfight so that pragmatic adjustments can be made, people in Northern Ireland can get used to new arrangements and the temperature can come down. As the durability of the Good Friday agreement in its 25th anniversary year faces perhaps its greatest challenge yet, it is high time that the UK government prioritised Northern Ireland again, instead of risking it becoming a permanent Brexit casualty. The very least it deserves is another of those “it’ll never happen” moments. Peter Hain was secretary of state for Northern Ireland 2005-2007