Paul the Wolf
Score Predictions Competition Organiser
I guess the only way to grow the population without immigration would be to encourage the indigenous population to have more children. For that you would need much higher levels of social security, namely free nursery places, more and better social housing and bigger tax breaks for parents etc. Zero chance of anything like that happening under a Tory government.
Although the Uk has the fourth highest birth rate in the EU behind Ireland, France and Sweden but none of them are enough to grow the population alone.