The Ulster Unionist Conference will be addressed this morning by the Northern Secretary, Mr Paul Murphy.
His address will be made following an invitation from the party, but he is not expected to touch on any subject thought likely to upset ongoing delicate talks between the party and Sinn Féin. A trusted source at Stormont suggested Mr Murphy would be "obviously cautious" in his remarks.
However Mr Murphy is expected to provide a positive analysis of the political benefits of the Belfast Agreement and the potential it holds for Northern Ireland in general, and unionists in particular.
Should elections be called next week, it will fall to Mr Murphy to sign the order which goes before parliament authorising a poll.
The conference will first debate a motion on terrorism calling on the British government to ensure its "stated determination to wipe out terrorism, both internationally and in Northern Ireland should remain the foundation block for political progress".
The Northern Secretary's address follows this debate and Mr Trimble will then make his keenly-awaited keynote address.
A reliable unionist source told The Irish Times Mr Trimble will talk-up the benefits to unionism of the Belfast Agreement, but will also include criticism of Sinn Féin.
He is also expected to refer to attempts to have the three MPs who resigned the party whip at Westminster reinstated.
Efforts have been made, following the passage of legislation flowing from the Joint Declaration, to have Mr Jeffrey Donaldson, Mr David Burnside and the Rev Martin Smyth retake the whip.
However, they have complained of being made to jump through hoops before such a move. The three quit the whip last June after differing with the leadership over the party's response to the two governments' Joint Declaration which was published last May. The three want the UUP to oppose it, while Mr Trimble favours a "tough but nuanced" approach.
Delegates will have an opportunity to raise their concerns in the afternoon during a question and answer session. The conference will also discuss proposals for a European constitution and a panel will discuss 'The European constitution - the death of UK democracy?'.
Mr Hugh Orde, the Chief Constable of the PSNI, will be present for a panel discussion on policing, as will Alan Murray, a security journalist.