//Bits of the country may be overpopulated but I think that is mainly in England or Glasgow and Edinburgh.//
There are 38 conurbations in the UK with a population density of more than 10,000 people per square mile. All of them bar one (Cardiff) are in England. Nine of the top ten are in southern England with only contender outside that area to make the top ten being York. Edinburgh weighs in at number 39 on the population density list with 9,990 people per sq. mile whilst Glasgow is at a lowly number 75, at 3,390.
The population density in Greater London is 14,500 people for each of its 670 square miles. This means every Londoner has a little over 200 square yards each to call his or her own. This is a space less than 15 yards square. But this does not tell the whole story. Population across London is very varied, with the inner London boroughs having a density over twice as high as the average. Islington is the most densely populated, with around 38,000 people per square mile. Four other boroughs – Hackney, Kensington & Chelsea, Lambeth and Tower Hamlets have more than 30,000 people per square mile. Bromley, Havering, Hillingdon and Richmond all have densities of under 10,000 people per square mile with London’s largest borough – Bromley, weighing in at around 5,400.
The overwhelming majority of the 1.2m people who arrived to settle in the UK in 2022 do not want to live in Scotland; they do not want to live in Wales or Cumbria or the West Country. They want to live in London and the South-East. Comparing the population density of the UK (around 700 per sq. mile) with other countries is not very useful.