George Maggs works as a constituency coordinator for Charlotte Leslie MP and is a final year PhD researcher at the University of the West of England. He writes in a personal capacity.

Immigration never seems to shift far from the headlines. In Theresa May’s excellent speech on Brexit last week, the primary reason she gave for not seeking to continue Britain’s membership of the so-called ‘Single Market’ was that it would entail the preservation of the principle of free movement and continuing unlimited immigration from the EU.

In November, new statistics came to light which showed that immigration into the UK last year remained at record high levels, with a net total of around 335,000 people arriving in Britain. That’s almost the equivalent of the entire population of Cardiff entering the country in just 12 months.

The current levels of immigration are unprecedented in human history and, whilst we are frequently informed by cosmopolitan liberal commentators that we are a ‘nation of immigrants’, the fact remains that we have permitted more people to enter the country in the last 15 years that the previous 1,500 combined.

The question is: should we view this mass arrival of individuals as a positive phenomenon and as a vote of confidence in our great nation, or as a cause for grave concern? Inevitably, the answer lies somewhere in between, and I do not wish to debate the rights and wrongs of mass immigration here, nor to discuss the economic positives and negatives which derive from it. Rather, I want to try to convey why I think so many people are worried about immigration, and why it is frequently cited as the number one concern for people in opinion polls across the Western world.

The reason people are increasingly anxious about this issue is not because they have suddenly become more racist or xenophobic; because they fear the economic consequences; or even because they are worried about the impact high levels of immigration can have on wages and public services. Rather, it is because it cuts to the very heart of why countries exist at all.

At the signing of the Treaty of Westphalia in 1648, an international convention was established which set a precedent of non-interference in countries’ domestic affairs. States, in effect, became sovereign, and each nation was left to its own devices, to govern its populace in a manner which best suited that states individual needs. This treaty became the foundational text governing international relations for the next 350 years.

Implicit in the establishment of this convention was the acknowledgement that nations and the people who inhabit them share a collective identity and a broad agreement on the way their country should be governed. Although of course internal disagreements have always arisen, and often spilled out into violence, the reason countries were originally created was to expel foreign influence, and allow communities and peoples to pursue a collective self-determination. Nations became free to create their own institutions, legal systems, establish their own state religion, and produce systems of governance to which all citizens could engender a sense of loyalty towards.

Immigration from nations which share similar cultural practices, constitutional and legal systems, attitudes and faiths therefore pose a much reduced risk of upsetting this consensus. This is reflected in public opinion. In March, a Royal Commonwealth Society survey found that 58 per cent of the British public, 75 per cent of Canadians, 70 per cent of Australians and 90 per cent of New Zealanders support the free movement of people between our four nations. This contrasts markedly with a recent YouGov poll which found that only 17 per cent of the British public supported allowing more refugees into the country, with 69 per cent stating that immigration controls in general should be tightened. In Australia, one Essential Report poll released in September found that fully 49 per cent of Australians would like to ban Muslim immigration altogether.

People therefore are not concerned about the numbers per se, but rather are fearful of the impact on their individual country and community when large-scale immigration emanates from parts of the world with very different attitudes and cultural practices to their own. This feeling is exacerbated still further when some sections of newly arrived immigrants appear to have little desire to integrate into wider society.

Louise Casey’s recent report on integration, published last month, found that in parts of Birmingham, Blackburn, Burnley and Bradford where up to 85 per cent of the local population are Muslim, people tend to hold “very socially Conservative views” about women and homosexuality. With few British Muslims marrying into the broader population, cultural traditions and even legal practices through Sharia Courts have been reproduced and reinforced.

The extent of this cultural diversity creates significant difficulties for an international system of nation states founded upon the principles of national self-determination and broadly shared communal identities. When, for example, one section of a society wants homosexuality to be illegal while others want to see homosexual partners free to marry and adopt children; or when a majority wish to liberalise social practices and enhance gender equality while others want to see women segregated and covered in public; it is difficult to conceive of a national identity able to provoke a sense of belonging within all members of society.

For the majority, the numbers in themselves are not the real problem. Nor are the alleged economic issues, or the perceived impact on services and incomes. Instead, it is the number of individuals who arrive with such contrasting views to the rest of society, and the failure in large parts to integrate them into the wider community, which ignites such passion. In this sense, immigration cuts to the very heart of nationhood, self-determination, and personal and cultural identity. It is small wonder it has become the most pressing socio-economic and political issue of our times.