Concern about polarisation has grown since the EU referendum in 2016. As the results were announced, the political establishment were quick to assert that the outcome “revealed a divided Britain”, and have since continued to reiterate the need for politicians on all sides to come together to deliver “a Brexit … that brings the country back together, rather than entrenching division.” 

This discussion of division has taken hold – and, in some cases, for good reason. We know that splits have formed along a variety of fault lines in the UK, be it by where we live, our age, level of education, or how we voted in the EU referendum. And in recent days, weeks and months, the fragmentation of our political system has become ever more evident.

But the extent to which the population is divided to the extremes suggested by headlines and political rhetoric is unclear. Part of the problem is that there is little clarity on what we mean by polarisation, which is implicit in the “Divided Britain” narrative – nor on how we measure it. Indeed, the challenge facing politicians and policymakers who aspire to “heal a divided Britain” is that there is actually little consensus over the specific nature and scale of the problem, let alone what could be done to solve it.

Part of the challenge lies in the lack of conceptual clarity around what polarisation really means. Too often, terms such as “division” and “polarisation” are either used interchangeably or accepted as simple and universally understandable. But when you start trying to measure them, it becomes apparent that they’re actually complex and contested concepts.

There are signs that the UK has grown “affectively” polarised. The identity attachments formed around Brexit in particular appear to run far deeper than traditional party affiliation, taking on an almost tribal quality. “Leaver” and “Remainer” identities had already taken hold in the months following the referendum, with a dominant view of the opposition as “hypocritical”, “selfish” and “closed-minded”, and a growing reluctance to socialise across the dividing line. And even now, these identities still seem to be splitting families, causing break-ups and ending friendships.

But this is different to polarisation on issues, which assumes people make informed, rational choices, and hold political identities consistent with associated policy positions. Rather, theories of affective polarisation rest on the premise that much political behaviour is not rational or fair-minded. Affectively polarised groups can dislike each other intensely without showing substantial disagreement in their positions on salient issues, dividing themselves socially and disliking others on the basis of whether they identify with their own or an opposing side.

These more emotive, affective forms of polarisation are distinct from polarisation around issues. Yet even this requires more than a difference of opinion. Disagreement is part and parcel of an open and democratic society; polarisation implies something more – that the divides in our society are so great that they prevent us finding a way forward. The salience of issues is also key – how much people care about a given issue can influence how polarised the environment feels.

Coherence in these conceptualisations matters. As the idea of a divided Britain continues to take hold, we urgently need to come to a shared understanding of what we actually mean by polarisation, and whether such divisions are representative of the population at large or reflect the position of a much smaller, politically engaged group.

The EU referendum raised important questions for policymakers about divisions and inequalities in our society. Whether these differences are real or imagined, fixed or shifting, is of deep consequence.

Rather than focusing on such dichotomous groupings such as “Leave/Remain”, “Closed/Open” or “Somewhere/Anywhere”, which artificially reduce the population into competing camps, we need to do more to draw out the full spectrum of opinion, values and attitudes, to identify common ground for respectful discussion and debate, rather than continuing to give disproportionate weight to the opinions at the most extreme ends of the spectrum.

We urgently need to nuance how we think about and discuss division in the UK. As we argue in our report out today, we need to take more care in our use of polarisation and related concepts, as we may be mischaracterising the important changes we’re seeing in the UK.

It is difficult to avoid the conclusion that Britain is dividing, but not in the way that’s commonly described – not into two monolithic blocs around Brexit. It has been longer in the making than that, with more dimensions. Understanding this more fully to develop approaches that bring us together is vital, to avoid further embedding social conflict and political gridlock.

Dr Kirstie Hewlett is a Research Associate at the Policy Institute, King’s College London.