British Prime Minister David Cameron and Ireland's Taoiseach Enda Kenny attempt to prevent collapse of power-sharing after allegation that the PIRA still exist.Photocall

The prime ministers of Britain and Ireland, David Cameron and Enda Kenny, will join the Northern Irish peace talks in Belfast, on Thursday, in an attempt to forge a last minute agreement. US Envoy former senator Gary Hart is also expected to attend.

Efforts to reach a compromise on issues such as parades, flags and emblems and how to handle atrocities on both sides during The Troubles has led to an impasse between the power-sharing government of the Democratic Unionist Party under Peter Robinson and Sinn Fein under Martin McGuinness.

There are real fears that the 7 and a half year old government could collapse without a new deal that would include economic commitments. The negotiations face an informal Christmas Eve deadline.

Deputy First Minister Martin McGuinness of Sinn Fein stated Tuesday that the window for a deal is closing fast as the British General election to be held in May will freeze Northern Irish politics.

McGuinness said that the arrival of the two leaders is "a very clear indicator that people recognize we are coming to the crunch in these talks."

Failure may mean direct British rule from London, which was in place from from 1972 to 1999, before the U.S.-brokered Good Friday peace pact.