Did Brexit Break Belfast? Mass Migration and the Six Counties

One of the most frequently repeated promises made during the Brexit campaign was that leaving the European Union would “end mass migration”. Nearly a decade on, that claim does not survive contact with official data.

On the contrary, immigration into both Britain and in the Six Counties has only increased since the referendum and Britain’s formal withdrawal from the EU in 2020.

This is not a matter of opinion or ideology. It is a matter of publicly available statistics.

Immigration into Belfast before and after Brexit

At city level, the most reliable source available is the 2021 Census for the Six Counties, published by the statistics agency (NISRA). While the Census does not record annual inflows directly, it does record the year of arrival of people resident in Belfast on Census Day (21 March 2021). This allows for a clear comparison of trends over time.

Between 2011 and 2015, the number of people arriving to live in Belfast each year averaged around 1,700. From 2016 onwards, that figure rises sharply. By 2019, nearly 5,000 Belfast residents reported arriving in that single year and in 2020 the figure exceeded 6,000. Even allowing for the exceptional circumstances of the pandemic period, there is clear pattern where the years following the Brexit referendum saw substantially higher levels of inward migration into the city than the years before it.

Taken as a whole, the total number of Belfast residents in 2021 who reported arriving between 2016 and 2020 was more than double the number who arrived between 2011 and 2015. Whatever else Brexit may have changed, it did not bring about a reduction in migration into Belfast.

For clarity, these figures relate to the Belfast Local Government District rather than a wider “Greater Belfast” commuter area. It is reasonable to assume that broader metropolitan effects exist beyond the city boundary, but even when confined strictly to Belfast itself, the upward trend is clear.

Britain-wide trends

‘UK’-wide data published by the Office for National Statistics helps to explain what is happening in Belfast and the rest of the North of Ireland, which has open borders with Britain.

Since the Brexit referendum, net migration into Britain has reached record highs. The crucial change has not been a reduction in overall numbers, but a shift in composition. Net migration from the EU has fallen. At the same time, non-EU migration has risen dramatically, driving total net migration to levels well above anything seen before Brexit. This is associated largely with the more liberal universal points-based system that applied to all nationalities, which enabled large numbers of non-EU migrants to enter under work, study, family and other visa categories.

In other words, Brexit ended EU free movement, but it did not end mass migration. It replaced one system with another, while leaving overall numbers higher than before.

This is where an error in reasoning enters the debate. A friend of mine once joked that eating eggs in the morning is bad for you, because one time he had three eggs for breakfast, climbed onto his roof, jumped off and broke both his legs.

Therefore, eggs are bad. Brexit is often opposed using a similar logic. Just because a number of policies and obligations were removed, any subsequent economic, social or even moral decline is often wrongly assumed to be related to that.

A brief comparison with the 26 Counties

For context, it is worth noting that the 26 Counties have also experienced high levels of inward migration in recent years. Official figures show net migration rising drastically after the mid-2010s, with particularly large inflows since 2022 and a majority of arrivals are now coming from outside the EU. This underlines a broader regional reality that high migration is now a feature of policy choices made across both Britain and Ireland rather an anomaly confined to one city or one country.

What the data does (and does not) show

A brief note of caution is necessary. Census “year of arrival” data captures only those who were resident in Belfast in March 2021, it does not include those who arrived and later left, nor does it provide a perfect annual flow series. Net migration figures are national rather than local and there is no single dataset which can capture every aspect of population movement.

Nonetheless, taken together, these are the official sources available and they point in the same direction. Claims that Brexit would in itself bring migration numbers down have been proven wrong.

As with so many issues under partition, decisions taken elsewhere are imposed on the Six Counties and their consequences are felt locally regardless of the slogans and rhetoric used to justify them.

Conclusion

The lesson here is simply a factual one about political promises being untrue. Brexit did not ‘end mass migration’. In Belfast, the Six Counties and across the water, immigration only increased after the Brexit referendum. Any serious discussion of immigration policy must acknowledge that basic reality and abandon claims that the data has already rendered false.

At the same time, this does not mean that migration increased automatically or inevitably because of Brexit itself, just as my friend’s hypothetical injury was not caused by eating eggs. It increased because what replaced EU free movement was administered in a way that delivered higher inflows than the system it came in place of.