Explainer: What's caused the Stormont crisis?

Credit: PA Wire

Power sharing in Northern Ireland is on the brink of collapse following First Minister Peter Robinson's resignation - but what has caused the current crisis and what could happen next?

What's caused the current situation?

Former IRA commander Gerard "Jock" Davison in Belfast was shot dead in May. The senior republican backed Sinn Fein's peace process strategy following the 1998 Good Friday Agreement and was employed as a community development worker in his local neighbourhood.

Mourners at the funeral of Gerard Davison Credit: PA Wire

Another ex-IRA man, Kevin McGuigan, was murdered near his home in Belfast on 12 August. He and Mr Davison had been embroiled in a long-running personal feud and he had been suspected by many within the republican community of involvement in the murder three months earlier. There is widespread speculation that Mr McGuigan was killed in a revenge attack carried out by Mr Davison's IRA associates.

Police Service of Northern Ireland Chief Constable George Hamilton said the IRA still existed, but was not on a "war footing". Following crunch talks with political figures at PSNI headquarters, Mr Hamilton said the IRA were committed to "promoting peaceful political republicanism".

Kevin McGuigan was shot near his Belfast home Credit: PA Wire

However, the Ulster Unionist Party said trust in Sinn Fein had been destroyed and said it would resign from the Executive. The Democratic Unionist Party also claimed evidence showed that IRA activity was of sufficient strength to expel Sinn Fein from the Executive.

Since then and after arrests of leading republicans, the DUP has threatened to resign if power-sharing was not adjourned, resulting in Peter Robinson's resignation on 10 September.

What happens next?

Finance minister Arlene Foster has stepped into Mr Robinson's shoes after he and the majority of his Executive ministers resigned.

Mr Robinson also repeated his demand for the Westminster government to suspend the Stormont institutions outright to enable space for crisis talks addressing the implications of the murder of Kevin McGuigan to take place.

Theresa Villiers has so far refused to suspend the devolved institutions in Northern Ireland Credit: PA Wire

Northern Ireland Secretary Theresa Villiers rejected that call although she conceded that the DUP resignations would mean the functioning of the Executive would become much more difficult.

If no progress is made in resolving the situation, power in the province could revert to Westminster, although Ms Villiers has insisted she will not be suspending the devolved institutions, calling on the local parties to come together.

Has the Northern Ireland Assembly been suspended before?

The last period of direct rule from Westminster ended in 2007 but the Assembly has been shut down three times before, in the early years of power-sharing following the Good Friday peace agreement of 1998:

Peter Mandelson suspended the Assembly in 2000 over decommissioning of IRA weapons Credit: PA Wire

February 2000 - Secretary of State Peter Mandelson suspends the Assembly after the UUP/SDLP led Executive fails to strike a deal on IRA decommissioning. The institutions are restored in May after the IRA pledges to "completely and verifiably" put its arsenal beyond use.

August 2001 - In the absence of progress on decommissioning, despite proposals from the British and Irish governments outlined at Weston Park, Northern Ireland Secretary John Reid suspends devolution for 24 hours. The step was a political manoeuvre that effectively gave the parties a six week period to find a way forward on the thorny decommissioning problem.

September 2001 - With the IRA having pledged to intensify engagement with an international panel set up to monitor decommissioning, Mr Reid triggers another technical 24 hour suspension to give the parties further breathing room to get power-sharing back on track.

October 2002 - Sinn Fein's offices at Stormont are raided by the police as part of an investigation into an alleged IRA spy ring at the heart of government. A major political crisis erupts and ten days later Mr Reid suspends devolution and announces the return of direct rule by UK Government ministers.