UUP leader Doug Beattie has expressed pessimism about the likelihood of the Stormont assembly being restored this year.
The assembly has been collapsed for more than a year amid DUP protest action over post-Brexit trading arrangements.
Earlier this year, the UK re-entered negotiations with the EU and agreed the Windsor Framework to address some of the unionists’ concerns around the Northern Ireland Protocol.
However, DUP leader Sir Jeffrey Donaldson has said some issues remain and is in communication with the UK Government over this.
Mr Beattie attended the Conservative Party conference on Monday and challenged Sir Jeffrey over his stance.
“The Government is going to operate this regardless, what are you going to do to stop it, what are you going to do to help the people of Northern Ireland?” he told the BBC.
“What is the plan? And if the plan is nothing but to complain and say ‘stay out’, well, there is no plan whatsoever.
“The reality right now is that this conference here isn’t talking about Northern Ireland, this conference isn’t focused on the Windsor Framework, this conference is looking at how do we improve the whole of the UK’s standing globally.
“What we need to do in Northern Ireland is make Northern Ireland work by making Northern Ireland a working part of our United Kingdom.”
Asked about the prospect of the Stormont assembly returning this autumn, Mr Beattie said he is “as pessimistic as I have ever been”.
“I have tried to be optimistic but I’m as pessimistic now as I have been been, the Government isn’t talking to us, we don’t know what is on offer,” he said.
“I have a meeting with the Secretary of State (Chris Heaton-Harris) later on and I’ll put some questions to him, but the reality is we haven’t been in the room as part of these negotiations.
“The DUP have, Jeffrey Donaldson has, it’ll be up to them to show courage and that leadership to say we need to start working for the people of Northern Ireland while at the same time challenging the issues of the Windsor Framework.
“The UK Government is moving on, if we are unionists and we believe in the whole of the United Kingdom, we need to be a functioning part of it.
“I get a lot of grief for my stance, but I’m as strong a unionist as anybody. I think our protections within the union can be found within the Belfast Agreement, and that means being in Stormont.”