High housing costs are a disaster for living standards, costing private tenants over 30 per cent of their income and giving London the highest poverty rate in the United Kingdom.

The answer for economists is to build more housing in expensive areas, but it is easier said than done. Developments are often opposed by the right to lower local housing prices and by the left against gentrification.

Opponents rightly say that downtown developers are building for richer customers.

But the lasting impact of construction goes beyond the immediate impact of who moves into that property when a new owner moves out of their current home and creates an opportunity for someone else. When this continues, it means that building in one area can help reduce costs elsewhere.

But is that happening in practice? Yes, at least in Helsinki, the answer is a new research. When studying new buildings in the center of the capital, researchers show that better-off people move in. But they continue to follow the next migration chains and surprisingly quickly see lower-income and lower-income neighborhoods join the chain. Only 20% of those moving to new downtown buildings are from the poorest half of the population – but the proportion rises to 50% when you are five years old.

Thus, the increased supply of housing has city-wide benefits, even if it takes place in the city center. Crucially, this is true where cities are less isolated, so different groups move between regions and the benefits of social housing spread more quickly. So we should not oppose development – we should build inclusive cities.