There has been excited chatter in recent days that a breakthrough on the Northern Ireland Protocol could be imminent. Last week, the UK government and Brussels agreed a new technical arrangement on sharing trade data, which was heralded as a ‘new basis’ for talks, following a meeting between EU chief negotiator Maros Sefcovic, and James Cleverly, the Foreign Secretary. Since then, there has been speculation that the two sides could enter the ‘tunnel’ – the intensive end stage of negotiations – as soon as this week. There is a desire on both sides to find an agreement on changes to the Protocol could ahead of the 25th anniversary of the Good Friday Agreement.

However, today Downing Street urged caution – with No. 10 declaring that there are ‘still significant gaps’ between the two sides, so it is unlikely talks will go ‘into the tunnel’ any time soon. It comes as Sefcovic and Cleverly – along with Northern Ireland Secretary Chris Heaton-Harris – met over video link to discuss the remaining challenges, agreeing to continue in a ‘constructive and collaborative spirit’. It’s still possible for things to move more quickly than Downing Street is letting on; both sides are trying to give out as little information as possible on the state of play so as not to impact any progress. But there’s another reason that Rishi Sunak would be wise to tread carefully when it comes to finalising any agreement: the groups he needs to win approval from.

Sunak could choose to press on, knowing that he was unlikely to win the support of the DUP. But what about his own party?

The biggest concern both among the DUP and members of the European Research Group of Tory Brexiteers is the role of the European Court of Justice, with the UK arguing for an independent arbitrator to govern trade between the two sides. Should a deal fall short here, the DUP is unlikely to back it. Notably the party’s leader, Jeffrey Donaldson, has said the UK and EU are not ‘anywhere close to a deal’ that would pass muster. If the DUP doesn’t back it, then any deal won’t offer a solution to the deadlock at Stormont. In a sign of awareness of this, Cleverly said this week that ‘having the parties coming back to Stormont and getting resolution on the Northern Ireland Protocol are not necessarily interlinked’.

Sunak could choose to press on, knowing that he was unlikely to win the support of the DUP. But what about his own party? Just last week, Boris Johnson used his speech at the Carlton Club – to mark the unveiling of a portrait of himself – to say only that the Conservative party ‘believes in the union with Northern Ireland and will pass the necessary laws to protect the economic integrity of the UK’. The comments will add to talk that Johnson could make an intervention on the Protocol if he decides a deal means capitulation. There are plenty of Tory Brexiteers who could rally behind him on the issue. It means that even if Sunak could still get any agreement through – and Keir Starmer last week offered Labour support – the Prime Minister could still face very difficult territory politically with his own side.