BBC NI Political Editor Mark Devenport interviews David Cameron at the Conservative Party conference in Birmingham.
Attempts by the Conservative Party and the UUP to form a new political movement are facing some difficulties, Tory leader David Cameron has admitted.
The Ulster Unionists' only MP, Lady Sylvia Hermon, has so far not committed to taking the Conservative whip.
"It's a lot to ask of people, not to change their allegiance, but to look into the future and say 'we can make this work'," said Mr Cameron.
He said he "passionately" believed such an arrangement could be achieved.
"It's a chance to make Northern Ireland politics less sectarian and more about the issues we deal with right across the United Kingdom," he said.
The Conservative leader said that he did not believe agreeing a link with one Northern Ireland party would prove an obstacle to his ability to be an honest broker, should he become prime minister in the future.
At the weekend, Conservative peer and former UUP leader Lord Trimble announced that the party would fight for every seat in the UK, including Northern Ireland, at the next General Election.
Lord Trimble told the Conservative Party conference in Birmingham he hoped the party would have the help of the UUP at the next election.
However, DUP junior minister Jeffrey Donaldson has warned that any merger between the Conservatives and the Ulster Unionists would be damaging for unionist co-operation at future elections.
Mr Donaldson, who is hosting a fringe meeting at the Conservative conference on Monday, said: "How on earth do we build unionist unity if, as Lord Trimble announced on Sunday, the Conservatives and Ulster Unionists are going to contest every seat in Northern Ireland.
"This means we won't have a unionist pact in south Belfast or in Fermanagh and South Tyrone, and once again those seats will be won by nationalists by default because unionism can't agree."
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