Do you have evidence for your claim of 'trend', Red? Forgive me if I am suspicious. Prime agricultural land is going for upwards of ?15K / acre these days. Which is not a lot if you can stick twenty shoeboxes on an acre, I grant you.

However, you have to apply for planning permission. And, I believe, not only is there a general category of 'use of land', there is also a reluctance to allow that use to change. It's not as simple as buying an acre of farmland & applying for planning permission for a house. The change of use of the land has to be approved from agricultural to residential. As far as I am aware, councils are rather reluctant to change the usage of agricultural land. You're right about net importer, though. In fact, we were a net importer before WWI never mind Mk II!