The Battle of Northern Ireland was a full-scale war between Ireland and United Kingdom for Northern Ireland. The war began when the Irish Army launched a massive Invasion of Northern Ireland on November 30, 2015. The Queen of England urged Irish government of pulling their forces out of Northern Ireland. The Irish refused and the United Kingdom declared war on Ireland on December 2, 2015.
Before the Invasion, Republic of Ireland was asking the British government to transfer and secede Northern Ireland to them. The British refused which strained the relationship between the two nation, which had historical ties. On November 3, 2015, the Irish government began increasing the number of troops on the Irish-Northern Irish/UK Border. A small-scale battle accidentally happened as the Irish Army and British Army exchanged fire, 30 people were killed.
On November 30, thousands of soldiers of the Irish Army, Supported by Russia, crossed the border, thus beginning the Invasion. The British Government gave a ultimatum to the Irish, demanding the retreat of their forces. Of course, the ultimatum was ignored, and on December 2, 2015, Her Majesty's Government declared war on Ireland and began mobilizing their troops. The United States, Canada, and France backed and supported the United Kingdom.
The War lasted until April 14, 2016, when the Irish Government signed the Instrument of Surrender. More than 120,000 Irish were killed and 60,000 injured. The British casualties were over 100,000 deaths. The battle was unsuccessful and Michael D. Higgins was removed out of power.