The Ulster Unionist leader Mr David Trimble is to meet the British Prime Minister in London tomorrow as efforts continue to move the peace process forward.
"Mr Trimble is to meet Mr Blair in the House of Commons", a Downing Street spokesman confirmed.
Tensions between the Ulster Unionists and Republicans were mounting tonight after a Stormont Minister warned that Mr Trimble's sanctions against Sinn Fein would continue if the IRA failed to put its weapons beyond use.
Culture Arts and Leisure Minister Mr Michael McGimpsey told BBC Northern Ireland's Spotlightprogramme that while policing might be the "big issue for Republicans", Unionists regarded the issue of paramilitary weapons as being of paramount importance.
Mr McGimpsey also said he believed talks to resolve the deadlock in the peace process were going backwards.
PA