Immigration has become a potent symbol of the divide between big-city Britain and the rest of the country. Large metropolitan areas have the highest numbers of immigrants, and the populations most favourable towards immigration. Smaller towns and villages don’t have much immigration, and don’t see why they should want more.

This, at least, is the stereotype that has become dominant in public debate. The reality, this report argues, is quite different. Immigration has been quietly playing a crucial role in sustaining the life of smaller settlements.

Population decline can pose an existential threat to villages and small towns, and even in larger settlements it can be a cause of significant economic and social problems. A shrinking population – which, since the young are more likely to leave, is usually an ageing population as well – increases the demands on local services like social care and hospitals, and decreases the funds available to provide them. It robs local businesses of both staff and customers. And as the damage sets in, more people choose to leave the area, reinforcing the consequences.

The dangers of this vicious cycle are well understood in places like the United States, where shrinking populations have been one of the main problems afflicting cities and towns in the struggling Rust Belt. In the UK, the risk of local depopulation has only entered public debate in relation to remote parts of Scotland – but the true scope of this challenge is far broader.

Migration has been key to heading off that issue. Our analysis reveals that there are dozens of local authorities across England and Wales where the population would be shrinking if it weren’t for immigration. They are not, contrary to what the usual stereotypes might suggest, concentrated in major urban areas. Instead, places all across the country – from small coastal settlements to market towns in the Midlands to largely rural districts – have benefited from immigration sustaining their population, especially the working-age population. London and other big cities, too, have avoided the fate of places like Detroit thanks to migration heading off depopulation.

This vital contribution has not come because of deliberate policy or planning. That is a problem. It means that the potential benefits migrants can bring to places facing population decline are not being maximised. And it means they aren’t understood or appreciated, because local communities have not had a serious discussion about their population needs and how immigration can help meet them.

With better policy and better public debate, drawing on lessons from Australia, Canada and the US, our immigration system can come to better serve the needs of the whole country, and recognise the vital contribution migrants are making to communities across the entire UK. This report shows how.