DUP support for a deal which will return devolved government to Northern Ireland is “absolutely decisive”, party leader Sir Jeffrey Donaldson has said.

The DUP leader said he recognised there were colleagues who had “ongoing concerns” but he said work would continue over post-Brexit trading arrangements.

The unionist party supported the proposals agreed with Government that will end routine post-Brexit checks on goods shipped from Great Britain to final destinations in Northern Ireland following a marathon five-hour executive meeting on Monday.

However, shortly after the Government unveiled the Safeguarding the Union deal on Wednesday, they were attacked in the Commons by DUP MP Sammy Wilson.

Mr Wilson raised concerns that a returning Stormont executive would have to “adhere to and implement laws which are made in Brussels”.

He added: “This is a result of this spineless, weak-kneed, Brexit-betraying Government, refusing to take on the EU and its interference in Northern Ireland.”

Appearing at a press conference alongside Northern Ireland Secretary Chris Heaton-Harris at Hillsborough Castle, the DUP leader said his party had examined the proposals in detail.

He said: “They have considered them and on Monday evening I was given a decisive mandate by my party executive to proceed on the basis that we have outlined and which is now unfolding.

“I recognise there are colleagues who have ongoing concerns and there is more work to do. I will work with those colleagues to deliver the further change that is needed in the future.

“But my party has assessed these proposals against our seven tests and we are satisfied that we have made substantial progress and sufficient to enable us to restore the political institutions.

“We will continue to work from within Stormont and at Westminster, and our MPs will be an important part of that process in seeking to deliver further change.”

Sir Jeffrey denied his party was divided over the new deal.

He said: “I don’t accept the characterisation that my party is split.”

“I think, as with any party, people have concerns and the good thing about my party is they can raise those concerns and we have talked through those issues.”

He said he had not asked for the voting numbers from Monday’s party executive meeting, but added: “There was a very wide margin of support for the position we have adopted.

“The vote was absolutely decisive.”

Sir Jeffrey also said there was a “trust issue” over whether the Government will follow through on its commitments.

He said: “I recognise, of course, that not just my colleagues, but the people in Northern Ireland have concerns about how things may progress.

“There’s a trust issue here. That trust issue is not in me, that trust issue is in whether the Government will deliver what they have committed to do.

“I believe that we have built into these proposals sufficient safeguards and leverage that enables us to deliver what is being done.”

He added: “We are being inundated, flooded, with messages of support from unionists right across Northern Ireland.

“I think these proposals are more than capable of selling themselves.”

Mr Heaton-Harris also responded to Mr Wilson’s claim that the Government was “spineless”.

He said: “I thought Sammy was being quite quiet and timid for him today, so that’s interesting.”