Northern Ireland profile

Head of state: Queen Elizabeth II

Prime minister: David Cameron

Secretary of state for Northern Ireland: Owen Paterson

First minister of NI Assembly: Peter Robinson

Deputy first minister of NI Assembly: Martin McGuinness

Image caption Peter Robinson (r) and Martin McGuinness (l) work in a partnership once seen as unthinkable

The Good Friday Agreement provides for the administration of Northern Ireland by an elected assembly and executive with ministerial posts distributed according to party strength.

The British government's Northern Ireland Office, headed by the secretary of state for Northern Ireland, oversees constitutional and security matters. It deals with economic and social affairs when the Northern Ireland Executive is not operating.

Northern Ireland returns 18 members to the British parliament.

Since 2007 power in the Northern Ireland Executive has been shared between two parties traditionally considered it be on the more extreme wings of Unionism and Republicanism - the Democratic Unionist Party (DUP) and Sinn Fein - while the hitherto more dominant and more moderate Ulster Unionists and SDLP have been marginalised at the polls.

The DUP's Peter Robinson succeeded veteran leader Ian Paisley as first minister, with Sinn Fein's Martin McGuinness serving as deputy first minister and de facto co-leader of the Executive.

The Rev Paisley, a firebrand Protestant minister, and Mr McGuinness, a former leader of the Provisional IRA, developed a surprising rapport. Mr Robinson, a long-time party worker rather than street campaigner, has continued to work with Mr McGuinness, although tensions remain in this unlikely marriage of convenience.

Mr Robinson had to step down as first minister briefly in 2010 during an investigation into a financial scandal involving his wife Iris, who was also a member of the Assembly and the British Parliament.

He was cleared of wrongdoing, and went on to complete the delicate process of devolving police and justice powers to the Executive. The DUP and Sinn Fein both saw their positions improve at the expense of other parties at the 2011 Assembly elections, and the coalition seems set to continue.