Taoiseach Bertie Ahern will meet British Prime Minister Tony Blair in London this morning for discussions on the European Union budget and the Common Agricultural Policy.
Mr Ahern will also use the meeting to discuss the state of the Northern Ireland political process.
In a statement, the Taoiseach's office said this year has seen "unprecedented progress" in the peace process, especially with the IRA statement ending its armed campaign followed by the decommissioning of its weapons.
"The Governments are determined that the opportunity that there now is for progress will not drift away. The Taoiseach and Prime Minister will consider how to inject momentum into the process in the New Year and are likely to meet again in January."
The allegations led to the collapse of power-sharing at Stormont and the re-imposition of direct rule in Westminster.
The three men - Sinn Féin's head of administration, Denis Donaldson; his son-in-law, Ciaran Kearney; and civil servant William Mackessy - are due to appear at Stormont today with Sinn Féin president Gerry Adams.
They claim to be victims of a plot in the security forces to bring down power-sharing.
Mr Blair and Mr Ahern's talks also follow yesterday's dramatic decision by the Public Prosecution Service in Belfast Crown Court yesterday to drop charges against three men accused of operating a republican spy ring at Stormont in 2002.
Mr Blair is engaged in an intensive diplomatic battle to win support for his proposals for the budget.
As well as meeting Mr Ahern, he will hold talks with Greek PM Konstandinos Karamanlis and Spanish premier Jose Luis Zapatero at Downing Street. Mr Blair met six other EU leaders yesterday.
