SIR Reg Empey's bold venture with the Conservatives bore the flagging UUP some early fruit in June's European election.

Jim Nicholson was re-elected ahead of the DUP for the first time ever and the party has found a distinct niche within Northern Ireland's crowded pro-Union political field.

But of late there have been murmurings of unease at the electoral alliance – notably from the South Belfast Association and the ongoing unhappiness of North Down MP Lady Hermon at the link.

However, in a pre-conference interview with the News Letter, Sir Reg passionately defended his party's alliance with the Conservatives, arguing that it is a unionist bulwark, potentially linking the UUP into the next Government.

He said that a link with a major UK party was shown to be crucial by Sinn Fein's all-island organisation and Fianna Fail's plans to stand north of the border.

He said that the alliance was a key reason why Sinn Fein President Gerry Adams' call for the British Government to become a "persuader for a united Ireland" will fall on deaf ears if David Cameron enters 10 Downing Street.

"Imagine where unionism would be if both Sinn Fein and the SDLP were effectively all-Ireland parties – where you would have republican and nationalist ministers from the same parties in the cabinet in Dublin and in the Executive in Belfast – and we're sitting there with our two arms the one length?" Sir Reg said.

"The direction that we've been taking over the last two years has been, in our discussions with the Conservatives, to place us at the heart of the Union.

"If I was ever looking justification for what we are doing, we need look no further than your issue (Wednesday) where (Gerry) Adams makes his pitch for the British Government to bring about a united Ireland and the Irish government to be a persuader for a united Ireland."

Sir Reg said that Mr Adams' recent tour of the US was to get the Americans to pressure the British Government into pushing unionists towards a united Ireland.

"That is his strategy. I believe that what we are doing counteracts that because what does Gerry do if he meets a future British Government and somebody from our party is staring across the table at him?

"His philosophy is 'The problem is the British Government'. If the British Government decides they have no strategic interest in Northern Ireland, then it makes sense, from his point of view, that they become the people who pressurise us.

"I believe that the speech Cameron made at our party conference last year and indeed subsequently, when he took that issue head on and indicated that he would not be neutral on the Union, was bringing to an end that doctrine of neutrality as far as British Governments have been concerned.

"That is the very antithesis of what Adams is trying to do."

But Sir Reg stressed that he is not just interested in combating Sinn Fein.