As the parties involved in talks on the future government of Northern Ireland take part in this week's key summit in Scotland, we take a look at the key issues and players.
The UK Unionist leader Bob McCartney is probably the most sceptical voice in the Stormont assembly so far as the Good Friday Agreement is concerned.
A barrister and former North Down MP, Mr McCartney is not convinced that the IRA has really given up all criminal or violent activity.
He is concerned that the organisation may have retained hand guns for use in community control.
Mr McCartney has campaigned against the abolition of NI's grammar schools
The UK Unionists are opposed to the compulsory coalition set up under the 1998 Agreement, which they regard as undemocratic, in as much as voters cannot change the nature of the devolved government.
Mr McCartney used his influence to help ensure that the DUP included a line in their Westminster election manifesto last year deeming any mandatory coalition under d'Hondt or any other proportional system as "out of the question".
When the DUP Deputy leader Peter Robinson told the Assembly recently that he would only accept such a coalition on a temporary basis, Mr McCartney likened the new DUP policy to being "slightly pregnant or slightly constitutional."
Besides constitutional questions, Mr McCartney has been a strident critic of the government over its plans to abolish academic selection and to introduce a new rates system based on the capital value of people's homes.
The UK Unionists believe this is part of a government policy to strong arm the major parties into a deal.
Mr McCartney has campaigned against the abolition of Northern Ireland's grammar schools and declared that he is willing to go to jail rather than pay his new rates bill.
He has suggested ratepayers should pay their current bill plus 10%.
The UK Unionist delegation at St Andrews will consist of the party leader and two support staff.