Jeffrey Donaldson, the Democratic Unionist party (DUP) leader, has vowed to perpetuate Northern Ireland’s political paralysis unless the UK government overhauls its Brexit deal with the EU. Donaldson told the DUP’s conference in Belfast on Saturday that he would not revive power sharing unless Downing Street met the party’s demands on the Northern Ireland protocol. The MP said removing customs checks on goods entering the region from Britain would not be enough for the DUP to return to the defunct Stormont executive and assembly. “Either the prime minister delivers the provisions of the protocol bill by legislation or by negotiation and ensures that our place in the United Kingdom is restored … or there will be no basis to re-enter Stormont. On this issue, it is not words but actions we need to see and we will judge any outcome on the basis of actions not words.” The DUP and other unionists believe the protocol’s imposition of a trade border in the Irish Sea weakens Northern Ireland’s position in the UK. The party’s decision to boycott Stormont, which cannot function without it, has pleased grassroots supporters but angered other Northern Ireland parties, dismayed the US and embarrassed the UK. Donaldson’s blunt reiteration of the party’s position was a rebuff to Liz Truss. The prime minister has said the protocol bill, which would empower her government to unilaterally change parts of the Brexit treaty, is sufficient reason to restore power sharing. She urged the party in June to “get on with it”, and repeated the sentiment last week. However, the DUP is waiting for the bill, which is currently at the House of Lords, to become law, and possibly utilised. With the UK buffeted by financial turmoil and the cost of living crisis, Downing Street has softened its tone on the protocol in an apparent attempt to cut a deal with Brussels and end the damaging quarrel. On Friday, the Northern Ireland secretary, Chris Heaton-Harris, expressed optimism about a settlement. Donaldson reaffirmed his commitment to power sharing. “For the benefit of those watching in London and Brussels, if decisive action is taken on the protocol that restores our place fully within the United Kingdom, this party will take its place once again in a fully functioning executive.” But the DUP leader said he would not settle for a compromise that left the protocol mostly intact. “Some lay great emphasis on cutting the number of checks on goods entering Northern Ireland from Britain. If that were to happen they say all our problems would be sorted notwithstanding that the protocol has not yet been fully implemented,” he said. “The truth of course is that the checks on the Irish Sea border are the symptom of the underlying problem namely that Northern Ireland is subject to a different set of laws imposed upon us by a foreign entity without any say or vote by any elected representative of the people of Northern Ireland.” However, some party insiders believe that should a deal emerge, Donaldson will try to sell it to supporters as a victory and lead the party back to Stormont. The alternative is an assembly election and the risk of another drubbing by Sinn Féin, which overtook the DUP as the biggest party in an election last May.