Stormont Castle, in east Belfast, the main meeting place of the Northern Ireland Executive.Photocall

The Democratic Unionist Party, Northern Ireland’s largest Unionist political party, is set to meet with British Prime Minister David Cameron today in an effort to prevent the collapse of the Northern Irish government.

The DUP meeting was announced in the wake of the Ulster Unionist Party’s decision to withdraw from Stormont, the seat of Northern Ireland’s power-sharing government.

A DUP refusal to serve with Sinn Féin would bring down the government.

The UUP withdrew from the Northern Irish executive yesterday, citing a breakdown in trust between the Unionist and Republican parties after the Police Service of Northern Ireland (PSNI) blamed the murder of Republican Kevin McGuigan on the Provisional IRA, implying that the group is still established and operating within Northern Ireland.

Murdered Republican Kevin McGuigan.

Murdered Republican Kevin McGuigan.

McGuigan, 53, was gunned down outside his home in the Short Strand area of Belfast on Wednesday, August 12. His death was said to be retaliation for the earlier murder of leading IRA figure Jock Davison in an internal Republican feud.

The UUP has since claimed that they can no longer serve in the Northern Irish government alongside Sinn Fein.

“Seventeen years on, we are told the IRA still exists, and that it has a command structure, at a senior level,” UUP leader Mike Nesbitt told The Guardian.

“We are also told members of the IRA have committed a murder on the streets of our capital city, working with another criminal gang, Action Against Drugs. And in response, Sinn Féin trot out their single transferrable speech of denial. That speech is threadbare. It has put a hole in the fabric of the [Good Friday] agreement,” he said.

UUP leader Mike Nesbitt.

UUP leader Mike Nesbitt.

Sinn Fein leader Gerry Adams refuted the claims that the IRA still exists or has any connection with his political party in a post on his website yesterday.

“There is no basis for the charges made against Sinn Féin by our political opponents and if this descends into a political crisis it is a direct result of their stupidity and party political opportunism,” Adams wrote.

“I don’t agree with the PSNI Chief Constable’s claim that the IRA exists – even in the benign way he paints it. The war is over and the IRA is gone and is not coming back,” he added.

Sinn Fein leader Gerry Adams.

Sinn Fein leader Gerry Adams.

Former US senator Gary Hart, a personal representative to US Secretary of State John Kerry, said in a statement, “The United States encourages all of Northern Ireland’s parties to continue to engage in dialogue to sustain and improve the functioning of Northern Ireland’s government. We strongly support Northern Ireland’s devolved institutions created by the Good Friday agreement and St Andrews agreement.”

Read more: Does the Provisional IRA still exist? Some think so