High Quality Content by WIKIPEDIA articles! The Ulster Unionist Party (UUP) ? sometimes referred to as the Official Unionist Party (OUP) or, in a historic sense, simply the Unionist Party ? is the more moderate of the two main unionist political parties in Northern Ireland. Before the split in Unionism in the late 1960s, when the former Protestant Unionist Party began to attract more hard line support away from the UUP, it governed Northern Ireland between 1921 and 1972 as the sole Unionist party. It continued to be supported by most unionist voters throughout the period known as the Troubles.