Stormont Castle
Northern Ireland's Parliament buildings at Stormont

Expectations are rising that the 2021 Northern Ireland census may act as a trigger for a referendum on Irish unification, but ‘new’ census questions on religious background and national identity are likely to shape the debate about Northern Ireland’s constitutional future, a new study reveals. 

While ‘sectarian head-counting’ has featured in Northern Irish politics since partition in 1921, the 1998 Good Friday Agreement (GFA) introduced a mechanism for a ‘border poll’ on Irish unification. The 2016 Brexit referendum has led to heightened debate about such a poll being held. 

Censuses in Northern Ireland have long attracted political interest and debate because they reveal much about changing demographics – for example, with the gradual erosion of the Protestant majority argued to have contributed to a change in the Republican movement’s tactics from violence to the ballot box, in the expectation that Irish unification is inevitable once a Catholic majority emerges.

Publishing his findings in The British Journal of Politics and International Relations, University of Birmingham political scientist Dr. Laurence Cooley notes that addition of a question on ‘religion brought up in’ (added in 2001) has resulted in more people being classified as Protestant or Catholic than would be the case using the original religion question alone.

The religious background question has strengthened ‘two communities’ interpretations of census results and delayed the apparent disappearance of the Protestant majority, whilst an extra question on national identity (added in 2011) has complicated assumptions about whether citizens would support Irish unification.

Dr. Cooley commented: “Official statistics do not simply mirror, but help produce social realities. Given the combination of the border poll provision in the Good Friday Agreement and volatility created by Brexit, the political relevance of census results has increased. Many commentators are now viewing the 2021 census as a potential referendum trigger.

“Yet, new questions on religious background and national identity added to the census have created significant – albeit unintentional – consequences for debates about the constitutional future of Northern Ireland. Demographic change is a reality, but our understanding of it is shaped by the questions asked in the census. Most commentary has focused on whether a census revealing that those from a Catholic religious background outnumber those from Protestant backgrounds for the first time could trigger a border poll.

“However, the census also asks about national identity and the results from this question are likely to be far less binary. Rather than clarifying whether a border poll could be won, conclusions drawn from the results of the religious background and national identity questions may well point in opposite directions to one another. The census could therefore confuse as much as it clarifies when it comes to a potential border poll.”

Census results inform debates about the gradually narrowing gap between the size of the Protestant and Catholic populations, but the research demonstrates that insufficient attention has been paid the politics underlying the design of census questions.

The British government insists that the UK must leave the European Union as one, but the GFA was based on the assumption of EU membership. Given division between support for ‘Remain’ among nationalists and support for ‘Leave’ among unionists, there is renewed speculation about Irish unification. Brexit has heightened expectations that Northern Ireland might be reaching a ‘tipping point’ for Irish unity.

The GFA does not specify how it would be decided when to hold a referendum, just that one should be held if it appears likely to the British government that a majority would support a united Ireland. Given assumptions about the relationship between identity and constitutional preference, census results have featured prominently in discussion of possible triggers.

The ‘religion brought up in’ question added in 2001 came from the requirements of equalities legislation, whilst the national identity question added in 2011 was driven largely by attempts to align with ethnicity questions asked across the UK and satisfy EU citizenship data requirements.

In the last census, held in 2011, 45.1% of the population specified that they were Catholic or brought up Catholic, and 48.4% were from a Protestant or other Christian background. However, the results of the new national identity question were more complicated: 39.9% considered themselves British only, 25.3% Irish only, 20.9% Northern Irish only, with others specifying multiple national identities.

  • For more information, contact Tony Moran, International Communications Manager or call +44 (0)7827 832312.
  • The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 6,500 international students from over 150 countries.
  • “Census politics in Northern Ireland from the Good Friday Agreement to Brexit: Beyond the ‘sectarian headcount’?” - Laurence Cooley is published in The British Journal of Politics and International Relations and is available open access.