The growth that matters is per capita. That also removes the incentive to indeed "just add more people" to show GDP growth. Essentially, the UK is currently us

The growth that matters is per capita. That also removes the incentive to indeed "just add more people" to show GDP growth. Essentially, the UK is currently using immigration to prop up overall GDP figures and mask that the economy is at best stagnating, but more likely in decline per capita (I.e. People are getting individually poorer)