Sir – The letters from Jean Fooks on urban sprawl and from Sarah Redston on the Green Belt (August 20) are symptoms of a country not knowing what to do about the size of its population and the housing crisis.

We have a desperate need for more housing for our existing population, but we have a limited supply of suitable brown-field sites and (to my mind, quite rightly) want to preserve our green spaces and agriculture.

We also have limited control over population growth through immigration – and, in fact, we should be showing hospitality to more of the desperate refugees fleeing from war-torn countries.

We now need a national debate about what sort of country we want for our grandchildren in (say) 50 years’ time. Can we put a figure on a maximum population that we could reasonably sustain? Would we (in an extreme case) want to double the population, have lots of new skyscrapered cities, and rely even more (perhaps unwisely) on imports for the vital necessities of life?

Shall we say goodbye to our traditional countryside, destroyed by building and fracking, and hello to a totally robotic world? What sort of lifestyle and environment do most of us actually value?

As climate change takes effect and all our natural resources come under pressure, it is very difficult to get blinkered market-only-driven politicians to take population sustainability seriously. But as our country gets squeezed more and more, take it seriously they must. Otherwise the problems will only get much worse.

Don Manley
Oxford