The DUP will not return to a powersharing executive at Stormont until the Government acts to restore Northern Ireland’s status within the UK internal market, Sir Jeffrey Donaldson has insisted.

The party leader said he was a committed devolutionist and claimed direct rule from Westminster would result in bad decisions for the region, but he said Stormont could only work if it was built on solid foundations.

He made clear that changes to Brexit’s contentious Northern Ireland Protocol, which has created trade barriers on goods shipped to the region from Great Britain, had to be delivered before he would consider returning to a fully functioning executive.

Addressing a party election event at a cinema in Dundonald in east Belfast, Sir Jeffrey told colleagues: “The protocol must be replaced with arrangements that protect Northern Ireland’s place within the United Kingdom.”

The DUP collapsed the executive in February when its first minister Paul Givan resigned in protest at the protocol.

The move automatically ousted Sinn Fein deputy First Minister Michelle O’Neill from her job and removed the administration’s ability to meet or make significant decisions.

Powersharing rules mean a properly functioning administration can only be formed if the largest unionist and largest nationalist parties agree to enter the joint office of the first and deputy first ministers.

While polls indicate that the DUP is on course to be returned as the largest unionist party at May’s Assembly election, it is at risk of losing its status as the biggest overall party to Sinn Fein.

Aside from the protocol, Sir Jeffrey has repeatedly refused to confirm whether the DUP would take the post of deputy first minister alongside a Sinn Fein first minister.

He did so again on Monday, though he did add that he was a democrat and would respect the election result.

The Lagan Valley MP also declined to definitively confirm whether he would remain an MLA if he is elected in May.

There has been mounting speculation that Sir Jeffrey may decided to co-opt a colleague into his Assembly seat and remain as an MP until such time as the DUP is prepared to restore the executive.

Sir Jeffrey said the replacement of the protocol must be achieved either by way of a negotiated agreement with the EU or by the UK Government acting unilaterally.

He said that the New Decade, New Approach agreement that restored powersharing in Belfast in 2020 contained a pledge from the Government to legislate to protect Northern Ireland’s place within the UK market.

“The UK Government has not delivered on that commitment,” he said.

“Until they do, I will not be going back into an executive that is required to implement a protocol that harms Northern Ireland every day.”

The DUP booked a cinema screen in Dundonald on Monday to showcase a party film on its Five Point Plan for the election campaign.

The plan seeks to fix the national health service; grow the economy; help working families; remove the “Irish Sea border”; and keep Northern Ireland’s schools “world class”.

Sir Jeffrey told fellow election candidates that a Sinn Fein victory in the election would lead to intensified calls for a “divisive” border poll on Northern Ireland’s constitutional status.

Asked again whether his party would serve as deputy first minister alongside a Sinn Fein first minister, he said: “I have yet to meet the political leader, football manager or business owner who sets out his or her stall on the basis of what happens if they’re defeated, or if they lose or if they’re not successful, and that’s not the business I’m in.

“I am a democrat, I will accept the outcome of the election. But I don’t want the outcome of this election to be a Sinn Fein victory leading to a divisive border poll and endless years of bickering and squabbling in Northern Ireland.”

Pressed on whether he would remain an MLA if elected, he said: “The reason that I am putting my name forward for election in Lagan Valley is because I want to return to Stormont and I want to lead the DUP Assembly team in Stormont.”

He added: “I am very clear, until these issues are resolved, then I can’t see that there’s a basis for forming an executive that is required to implement the protocol.

“So, I’m committed to devolution, I’m committed to the Northern Ireland Assembly, I’m committed to seeing Stormont deliver for everyone in Northern Ireland. That’s why I’m standing as a candidate in this election to lead our team forward and to win the election.”

He insisted that devolution was the best form of governance for the region.

“Devolved government in Belfast gives unionists and nationalists a real say in many of the issues that affect our everyday lives,” he said.

“I want to see all of our political institutions up and running and working to deliver for the people of Northern Ireland.

“Our system of government is far from perfect, and needs further reform, but I believe in devolution.

“It’s good for unionism and it’s good for Northern Ireland.

“I don’t need to tell you that many of the decisions that we have objected to most over the last ten years have not been taken at Stormont but at Westminster.

“Anyone who believes that having no say in our future is a recipe for success simply hasn’t learnt the lessons of history.

“But we must build our political institutions on solid foundations.

“The protocol has harmed Northern Ireland and it does not enjoy unionist support.

“Pretending problems don’t exist is not a solution.”