Democratic Unionist party

The Democratic Unionist party (DUP) has recovered from a period of scandal as it continues its cautious powersharing arrangement with Sinn Fein.

The sexual and financial allegations faced by leader Peter Robinson's wife Iris Robinson threatened to leave a deep-seated trauma on the DUP in early 2010. But Robinson's decision to temporarily stand down from the first minister job to deal with threats to his own reputation appeared to have paid off.

Instead the party, sharing power with its arch-rivals Sinn Fein in Stormont, focused on making the devolution of policing and justice powers work. In days of intensive negotiations at Hillsborough Castle outside Belfast the prospect of a breakdown, which would have caused a snap election to the Northern Ireland Assembly, always loomed large. After the interventions of Gordon Brown and the Irish Taoiseach Brian Cowen a deal was finally reached, keeping the spirit of the St Andrews agreement alive.

The DUP does not just face challengers from republicans. Ever since its formation in 1971 it has had to live with schisms renting the unionist movement apart. Then it was a result of dissatisfaction with what its founders viewed as the appeasing stance of its predecessor Protestant Unionists. Now the Ulster Unionist party (UUP), which has allied with the Conservatives for the 2010 Westminster elections, is the main challenge.

The DUP had made impressive gains in recent years, after holding just two seats in Westminster in 1997. In 2010 it defended seven seats, making it the fourth largest party in the Commons. But it came third in the 2009 EU elections, perhaps hinting at a drift in further support.

The 2010 Westminster election saw a shock when Robinson lost his Belfast East seat to the Alliance party's Naomi Long. But it finished with eight seats overall, an increase of one. In 2011 the DUP emerged as the largest party in the Northern Ireland Assembly with 38 of 108 seats, winning 30% of the overall vote.