Rishi Sunak was warned on Wednesday that any post-Brexit deal for Northern Ireland must be “built on the support of unionists & nationalists”.
DUP leader Sir Jeffrey Donaldson was responding to speculation that the UK and EU are close to finally agreeing a deal to settle the long running dispute over the Northern Ireland Protocol.
He tweeted: “Restoring the Executive & Assembly requires the Protocol to be replaced with arrangements that reinstate NI’s place in the UK internal market & respect our constitutional position.”
Mr Sunak knows he needs to convince the DUP and Eurosceptic Tory MPs that any deal meets the pro-UK party’s seven tests on the Protocol.
The DUP wants the Protocol to be scrapped, arguing it creates damaging barriers to trade between Great Britain and Northern Ireland.
According to a report in The Times, negotiators from the UK and EU are close to agreeing a deal on removing customs checks on some goods moving between Great Britain and the region.
They were also said to be close to clinching a settlement to the row over the European Court of Justice’s jurisdiction to rule on trade disputes in the region.
But EU sources pushed back hard against the reports while Downing Street insisted intensive scoping work on the sticking points was continuing.
A UK Government spokesperson said: “Our priority is protecting the Belfast (Good Friday) Agreement and preserving political stability in Northern Ireland and the UK internal market.
“Any solution on the Protocol must address the range of issues on the ground in Northern Ireland.
“We are currently engaging in intensive scoping talks with the EU to find solutions to these problems.”
However relations between both sides have improved since Mr Sunak replaced Liz Truss as Prime Minister in October and negotiators are pushing to conclude a deal in time for the 25th anniversary of the Good Friday Agreement in April.
Sir Philip Roycroft, former permanent secretary at the Department for Exiting the EU, told Times Radio: “Clearly the Northern Ireland protocol has been a running sore in relations between the UK and the EU pretty much since the day it was meant to come into effect.
“So if they have now got a way of sorting out issues around the transit of goods from Great Britain into Northern Ireland, that frankly is good news.”
Negotiators are said to be working on plans to create green and red customs channels at Northern Ireland ports.
Those trucks carrying goods from Britain destined for Northern Ireland will be waved through the green channel while those set to travel on to the Republic of Ireland will face more stringent checks in the red lane.
But winning the support of the DUP for any agreement is not likely to be easy.
The party has set out how any new arrangements must “result in no checks on goods going from NI to GB and GB to NI” and “avoid any diversion of trade”.
The Protocol is part of the 2019 Brexit Treaty which paved the way for the UK’s departure from the EU three years ago.
It gave NI special status both in the EU single market and customs union as well as the UK’s internal market, thereby avoiding the need for a hard land border on the island of Ireland.
But business groups say the need for checks on goods travelling between Great Britain and Northern Ireland has added unecessary and costly friction to trade.
The DUP also says it drives a wedge between the region and the rest of Britain and says it won’t participate in the Northern Ireland Assembly until the row is resolved.