It's yet another legacy of the British stragey of divide and conquer. Still divided, still conquered..

Ulster was part of Catholic Ireland until the reign of Elizabeth I (1558–1603) when, after suppressing three Irish rebellions, the Crown confiscated lands in Ireland and settled the Scots Presbyterians in Ulster. Another rebellion in 1641–1651, brutally crushed by Oliver Cromwell, resulted in the settlement of Anglican Englishmen in Ulster. Subsequent political policy favoring Protestants and disadvantaging Catholics encouraged further Protestant settlement in Northern Ireland.

When the Republic of Ireland gained sovereignty in 1922, relations improved between North and South, although the Irish Republican Army (IRA), outlawed in recent years, continued the struggle to end the partition of Ireland. In 1966–1969, rioting and street fighting between Protestants and Catholics occurred in Londonderry, fomented by extremist nationalist Protestants, who feared the Catholics might attain a local majority, and by Catholics demonstrating for civil rights. These confrontations became known as "the Troubles."

35 years later, still divided, Britain is still in control.