There are currently some 50 million people in England, but by 2056 this could hit 68 million - 1,349 for every square mile.

The population density now is about 1,010. In London, the figure could rise from 12,377 to 13,910 over the next two decades.

The Tories, who obtained the data from the Office for National Statistics, demanded restrictions on migration levels.

Shadow immigration minister Damian Green said: "This demonstrates the real pressure public services are being put under as a result of Labour's immigration policy."

London aside, the biggest population rises will be in the East and South West of England, up 16% by 2029, while the North East is expected to remain static.

Scotland's level will remain the same at 171 per square mile; Wales will have 15% more residents by 2056 and Northern Ireland will have a fifth more.