Surprise talks involving the Conservative Party, Ulster Unionists and the Democratic Unionists could boost political support for David Cameron after a general election, it has been claimed.
The confidential discussions come as the Tories are already involved in an electoral pact with the Ulster Unionist Party (UUP), but the talks have fuelled speculation of a wider political deal.
The Conservatives have previously rejected DUP calls for agreed unionist candidates in selected Northern Ireland seats, characterising it as a return to old-style sectarian politics aimed at freezing out nationalists.
On Monday night the Conservatives said their shadow Northern Ireland secretary Owen Paterson had merely "facilitated" talks between the two unionist parties.
A spokesman said: "Mr Paterson held private talks with a number of senior unionist politicians in England over the weekend, the purpose of which was to help promote greater political stability."
But Northern Ireland sources claimed that the discussions were of wider significance and that while they were at an early stage, they could yet maximise unionist political strength in Northern Ireland, while also securing UUP and DUP support for David Cameron in a hung parliament.
An Ulster Unionist spokesman confirmed the three-party meeting took place in London, but would say only that the discussions were "on issues of mutual concern... including the stability of Northern Ireland".
DUP leader Peter Robinson is understood to have led the DUP delegation, though the party refused to comment on the discussions.
Speculation over the talks could have implications for the current political negotiations in Northern Ireland where Sinn Fein is trying to press the DUP into a deal on devolving policing and justice powers to Stormont.
The DUP faced pressure over the recent scandal that hit Iris Robinson, the wife of Mr Robinson.
Source: The Belfast Telegraph