 The Sunningdale Agreement, which led to the formation of a power-sharing Executive under Ulster Unionist leader Brian Faulkner, ruptured the party.In the 1973 elections to the Executive the party found itself divided, a division that did not formally end until January 1974 with the triumph of the anti-Sunningdale faction.Faulkner was then overthrown, and he set up the Unionist Party of Northern Ireland (UPNI).