In the immediate aftermath of this summer’s riots, what did the British public consider to be the most important issue facing the country? Immigration, the polls said, replacing the economy at the top of the worry‑list for the first time since 2017. So, what have politicians said they’ll do about it? The new Labour government wants to reduce it. Conservative leadership hopeful Robert Jenrick wants to cut it to the tens of thousands. Not to be outdone, Reform would freeze “non-essential” immigration entirely.

But the terms of this debate are wrong. The option to dramatically reduce or cut off immigration is an illusion. People are going to come here from overseas whatever we do, and what’s more, we need them to. No, the real choice is between a chaotic, punitive system based on political dishonesty, and a well-managed one that works, taking advantage of our good fortune in being a place that can draw people from around the world.

Despite massive policy changes, lurching from relative openness under New Labour in the early 2000s, to Theresa May’s “hostile environment” of the 2010s, to the end of free movement and the introduction of Boris Johnson’s surprisingly liberal system in the 2020s, migration to the UK has been very high by historical standards for the last 25 years. In this we are not an outlier: despite our very different histories and cultures, the proportion of the population that originates from abroad is almost identical to that in France or Germany.

This tells us that there are other forces than mere policy at work here – and they’re economic and demographic. The native-born labour force is already shrinking in almost all advanced economies; in the UK, essentially all the growth in employment over the last two decades – more than 4 million people – is accounted for by those born abroad. With fertility rates far below replacement level and the number of Britons over 65 set to increase by 5 million over the next 20 years, these pressures will only intensify. Without immigration, the numbers of people paying tax will shrink just as the numbers needing state support in later life are growing. It’s not a sustainable mix.

Theoretically, you could manage a shrinking workforce and a growing elderly population with very low levels of immigration. That would involve steadily automating more jobs, or simply accepting economic stagnation. But this seems pretty hard to imagine, as the examples of Japan and Korea suggest. Despite historically low migration and relatively “closed” cultures reinforced by language barriers, immigration to both countries has risen rapidly in recent years, driven by labour market pressures. Rather than resisting, both are now trying to attract migrants for both manual and skilled jobs – their prosperity and wellbeing depend on it.

So, levels of migration that are high by historical standards seem inevitable. This doesn’t mean politics and policy are irrelevant, though; on the contrary, they can make things much better or much worse. Broadly speaking, there are three options on the table.

The first is restrictionism: tight controls on legal migration for work and study, with only the most highly skilled allowed to stay, and no safe or legal routes for refugees. But in practice the laws of supply and demand mean many will still come, one way or another; and many will stay, one way or another, slipping into the grey zone of irregularity and the informal economy. The result will not in fact be massively reduced migration, but marginalisation, exclusion and exploitation – not just of irregular migrants, but of legal residents unfortunate enough to be working in the same sectors, who will also be affected by a race to the bottom. Ironically, this will provide further grist to the mill of anti-immigration politicians.

The second, and apparently more humane option, is advocated by those who recognise the economic imperative for legal immigration, but don’t like its consequences for our “national identity”. They would allow all but the most highly skilled workers to come on temporary contracts, along the lines of the Gulf states or Singapore, attempting to ensure that immigration did not result in permanent population change. But the European experience – the German Gastarbeiter programme, or even the expectation of many in the UK that the Windrush migrants would soon return to the Caribbean – shows this is entirely impracticable. Our societies just aren’t segregated enough, and people tend to put down roots. In practice, this too would result either in a growing irregular population, or a series of amnesties or other ad hoc responses.

Our current hodgepodge of migration policies and processes – it could hardly be called a strategy – has elements of both of these approaches. The previous government oversaw a regime of performative cruelty towards asylum seekers, an expansion of temporary worker schemes for agriculture, and increasingly onerous requirements for family visas and those who want to settle here permanently.

Yet we still have a relatively transparent and liberal work visa scheme, and the graduate visa for international students remains in place – although some of the political rhetoric of the last few years, coupled with the events of the last few weeks, have made it harder to attract those who can choose where they want to go.

With a new government in place, there is the possibility of a third option. We could start by recognising that our attractiveness to migrants, especially to those who want to come here to work and study, is a huge comparative advantage, not a problem. We have a relatively open economy, a major global city, and the English language. And we have close historical connections with by far the largest two countries that still have a bulge of well-educated young people looking for opportunities – India and Nigeria. This should be a source of hope and optimism, not fear. Not all societies facing the same economic and demographic pressures are so lucky.

But this would mean being honest about the fact that migration will continue at relatively high levels because we don’t, when it comes down to it, want either mass automation or stagnation. It should, therefore, be legal and regulated. But we also need a conversation about social consequences that isn’t rooted in an illusory “we can just stop them coming” option.

Thankfully, we are not, despite the scaremongering, a society irredeemably divided on ethnic, racial or religious lines. But running a successful multi-ethnic democracy in an era of continued high migration will not happen automatically, particularly given the political figures – seen out in force during the riots – willing it to fail. That means taking integration seriously again. To make a start, we should restore funding for English classes for new arrivals, move recognised refugees out of isolation in hotels and into homes and jobs as soon as possible, and reverse proposed changes to allow faith schools to select entirely on religious grounds. A system that works both for longstanding residents and new migrants, both as workers and people, is possible: now let’s debate that.

• Jonathan Portes is professor of economics and public policy at King’s College London.

Further reading

How Migration Really Works by Hein de Haas (Penguin, £10.99)

The Shortest History of Migration by Ian Goldin (Old Street, £14.99)

Move: How Mass Migration Will Reshape the World by Parag Khanna (Orion, £10.99)