SDLP leader Colum Eastwood addresses Ulster Unionist conference
The Social Democratic and Labour Party's Colum Eastwood has become the first leader of the party to address an Ulster Unionist Party conference.
The nationalist and unionist parties went into opposition at the Northern Ireland Assembly in May.
Mr Eastwood told the function that he wanted to see closer co-operation between the parties.
UUP leader Mike Nesbitt said: "Maybe next time we can persuade people if you vote Mike, you get Colum.
"If you vote Colum, you get Mike.
"If you vote middle ground, you get better."
In his speech, Mr Eastwood said the two parties had different policies and different visions of the future.
"Our Irish nationalism and your unionism will not seamlessly fit any time soon," he said.
"However, this difference does not diminish our ability to pursue the commonality of our immediate cause. Both the SDLP and the Ulster Unionists share the common ground of wanting to make Northern Ireland work.
"That's a healthy common ground to hold for today and tomorrow."
It was the first Ulster Unionist conference since the party went into opposition.
Mr Nesbitt attacked the two parties who form the Northern Ireland Executive - the Democratic Unionists (DUP) and Sinn Féin.
He said they were joined at the hip politically, yet the DUP played on unionist fears of Sinn Féin to get votes.
'Post-peace process society'
Mr Nesbitt said he not only wanted to see a post-sectarian society in Northern Ireland, but also a "post-peace process society".
"What is the peace process?" he asked.
"I'll tell you what Sinn Féin think it is, Sinn Féin think it's a weapon. Anytime something inconvenient comes along, Sinn Féin call it 'a threat to the peace process'.
"It helps maintain the illusion we remain in a state of transition, that there is something about our political challenges that needs special treatment."
He said both the DUP and Sinn Féin wanted to push the opposition parties around.
"It's not going to happen, conference," he added.