Källor: Nordirländskt parti ger sitt stöd till May

The Democratic Unionist Party (DUP) is the largest unionist political party in Northern Ireland. Founded by Ian Paisley and now led by Arlene Foster, it is the largest party in the Northern Ireland Assembly and the fifth-largest party in the House of Commons of the United Kingdom. The DUP has historically strong links to Protestant churches, particularly the Free Presbyterian Church of Ulster (the church Paisley founded) and has traditionally been regarded as the more Ulster loyalist of the two large unionist parties. However, this influence reduced somewhat under Peter Robinson's leadership in an attempt to reach out to non-Protestants, particularly socially conservative Catholics. Following on from the St Andrews Agreement in October 2006, the DUP agreed with the Irish republican party Sinn Féin to enter into power-sharing devolved government in Northern Ireland. In the aftermath of the agreement there were reports of divisions within the DUP. Many of its leading members, including Members of Parliament (MPs) Nigel Dodds, David Simpson and Gregory Campbell, were claimed to be in opposition to Paisley. All the party's MPs fully signed up to the manifesto for the 2007 Assembly elections, supporting power-sharing in principle. An overwhelming majority of the party executive voted in favour of restoring devolution in a meeting in March 2007; however, the DUP's sole Member of the European Parliament (MEP), Jim Allister, and seven DUP councillors later resigned from the party in opposition to its plans to share power with Sinn Féin. They founded the Traditional Unionist Voice in December 2007. The DUP is the largest party in Northern Ireland, holding ten seats at Westminster and 28 seats in the Northern Ireland Assembly. It has one seat in the European Parliament, where its MEP, Diane Dodds, sits as a Non-Inscrit. Although the party is primarily active in Northern Ireland politics, from 2004–05 it had one representative from the English constituency of Basingstoke, as a result of a defection to the party.