On the 22nd June 1921 King George V and Queen Mary arrived in Belfast for the official opening of the first Northern Ireland parliament. Fearful for their lives, they had come to a city scarred by bitter sectarian violence. The King’s visit to Belfast was the culmination of three centuries of history – and three years of political brinkmanship and brutal communal violence. The occasion marked the creation of the new state of Northern Ireland. A line had been drawn on the map – a new border that separated the north and south of the island.

One hundred years on, this is the story of the dramatic events that led to the partition of Ireland. A story that continues to reverberate to the present day - and dominate relationships between the islands of Britain and Ireland.