⁣Stanley Johnson - ex World Bank, Rockerfeller Foundation, MEP, former UN Ambassador - believes that the optimum UK population is 15 million (down from almost 70 million today)

http://www.stanleyjohnson.org/

The Population Problem 1973
https://www.amazon.co.uk/Population-Problem-Charles-sources-contemporary/dp/0715362828

World Population and the United Nations 1987
https://www.amazon.co.uk/World-Population-United-Nations-Challenge/dp/0521311047/ref=sr_1_1?dchild=1&keywords=World Population and the United Nations 1987&qid=1619648791&s=books&sr=1-1

The Daily Telegraph - Boris Johnson - 25th October 2007
https://www.telegraph.co.uk/comment/3643551/Global-over-population-is-the-real-issue.html