Northern Ireland border poll, 1973

Northern Ireland border poll
Northern Ireland within Great Britain & Ireland
Location	Northern Ireland
Date	8 March 1973
Voting system	Majority voting
Remain part of the United Kingdom   98.9% Join with the Republic of Ireland   1.1% Invalid votes   0.99% Voter turnout: 58.66%

Northern Ireland border poll	1973
United Kingdom EC referendum	1975
Scottish devolution referendum	1979
Welsh devolution referendum	1979
Scottish devolution referendum	1997
Welsh devolution referendum	1997
Greater London Authority referendum	1998
NI Good Friday Agreement referendum	1998
NE England devolution referendum	2004
Welsh devolution referendum	2011
United Kingdom AV referendum	2011
Scottish independence referendum	2014
United Kingdom EU referendum	2016

The Northern Ireland border poll was a referendum held in Northern Ireland on 8 March 1973 on whether Northern Ireland should remain part of the United Kingdom or join with the Republic of Ireland to form a united Ireland. It was the first time that a major referendum had been held in any region of the United Kingdom. The referendum was boycotted by nationalists and resulted in a conclusive victory for remaining in the UK.

The Unionist parties supported the 'UK' option, as did the Northern Ireland Labour Party and the Alliance Party of Northern Ireland. However, the Alliance Party was also critical of the poll. While it supported the holding of periodic plebiscites on the constitutional link with Great Britain, the party felt that to avoid the border poll becoming a "sectarian head count", it should ask other relevant questions such as whether the people supported the UK's White Paper on Northern Ireland.

The Social Democratic and Labour Party (SDLP), however, called for a boycott of the referendum, urging its members on 23 January 1973 "to ignore completely the referendum and reject this extremely irresponsible decision by the British Government". Gerry Fitt, leader of the SDLP, said he had organised a boycott to stop an escalation in violence.

The civil authorities were prepared for violence on polling day. They had put in place mobile polling stations which could be rushed into use if there was bomb damage to scheduled poll buildings. Two days before the referendum a British soldier, Guardsman Anton Brown of the 2nd Battalion, Coldstream Guards was shot dead in Belfast as the army searched for weapons and explosives which could be used to disrupt the upcoming referendum.

In response to the referendum, the Provisional Irish Republican Army planted four car bombs in London that day, two of which went off, causing one death and injuring 200.