Rishi Sunak is facing the biggest challenge of his premiership as former Conservative party divisions over hard and soft Brexit are re-emerging just as he appeared to be on the cusp of a deal with the EU to end the protracted row over the Northern Ireland protocol. Cracks emerging A sign that a deal was imminent emerged last Thursday when the prime minister held secret talks with the Democratic Unionists (DUP) into the small hours of Friday with EU Brexit negotiators also summoning representatives from all EU states for a briefing. Opponents in the wings and the cabinet At the weekend, opponents of a feared fudge stepped out of the shadows, with Boris Johnson, Simon Clarke, the former levelling-up secretary, Jacob Rees-Mogg and Suella Braverman all expressing reservations. Can Sunak do a deal without the DUP and ERG? Downing Street wants the DUP on board but the content of the rumoured deal and the timetable may not suit the party. Last week, Sammy Wilson, the DUP MP for East Antrim said the party would not return to Stormont if Northern Ireland remained “abandoned to the EU”. The EU is not going to agree to the end of the application of the EU law in Northern Ireland, as it is the bedrock on which the protocol is built and means no new border is erected between Northern Ireland and the Republic of Ireland. Commentators believe Sir Jeffrey Donaldson wants to return to Stormont but that the tough anti-protocol stance has boosted the party’s fortunes and will be a useful tool in the local elections in May. What has been agreed so far? Nobody is saying. The secrecy surrounding the negotiations has been extreme for fear of leaks. One source with knowledge of the talks said they knew that as soon as details leaked there would be “a feeding frenzy of piranhas on both sides” that could kill any deal at birth. Green lanes There are three main issues: the application of EU law in Northern Ireland to ensure no return of the hard border with the Republic of Ireland, the role of the European court of justice, and checks on goods crossing the Irish sea. The DUP and the British government want goods from Great Britain to flow as they did before Brexit – with no paperwork – arguing the protocol mandated the preservation of the UK internal market. The EU had insisted detailed customs paperwork be completed for all goods travelling from Great Britain to Northern Ireland to enable it to track products. Companies like Marks & Spencer have argued this is completely unnecessary as electronic stock taking allows them to see what goods are on what shelves in which location in real time. Is there a fix? Yes. Sources say the EU has agreed a compromise involving a carve-out for all goods destined for supermarkets, corner shops, canteens in schools, hospitals, prisons and similar “end” settings. Details of a settlement on “intermediary goods” that could end up in finished products exported to the EU were still being negotiated. The European court of justice This has long been a red line for the so-called Brexit ultras including veteran Eurosceptic Bill Cash and the deputy head of the European Research Group, David Jones. Is there a fix? Negotiators think there is by removing the ability of the EU to go straight to the ECJ if it sees there is an infringement or “infraction” of the trade rules. Instead an arbitration panel involving Northern Ireland and EU judges would be the first port of call in a dispute. Northern Ireland courts could also be involved in disputes over sanitary and phytosanitary controls on food and agriproducts that are devolved competencies. Application of EU law in Northern Ireland The ERG claims Northern Ireland is already drifting away from the rest of the UK with more than 400 pieces of legislation now applying there that do not apply in the UK and this will get worse. Is there a fix? Peter Hain has suggested a Norway-style deal giving Stormont ministers an official role on a committee that will assess and potentially amend draft EU legislation that impacts upon trade in Northern Ireland.