As suburban sprawl creeps its ever-expanding tentacles across swathes of productive rural land, as a society we need to produce more and more food from less and less land. Planners worry that at some stage we will not have enough land left to produce the volume and quality of food we require. Hence the desire to protect viable areas for farming.

Viability of farming enterprises is important. It is a matter of simple economics that larger farms tend to be more efficient, as they can spread their fixed costs over a greater acreage, giving a lower cost of production per acre.

For example, most sheep farms have a quad bike, which costs roughly the same whether you are farming 200 acres or 2000. You may be able to make do without a quad bike on, say, 20 acres, but everything will take longer. You would probably incur extra expenses elsewhere, perhaps in medical expenses when you hurt yourself carrying things which would be better transported on a quad bike!

Farmers tend to spend their working lives with a pencil behind their ear, scribbling figures on the back of an envelope, working out how they can acquire more land. Then they hit the problem of how to pass the farm onto the kids.

The tradition in Jane Austen’s England was for the eldest son to get the farm, the second son was bought a commission in the army or navy, the third son became a clergyman and the daughters married their money. While there were many faults with this system, one thing it did do was keep the estates as viable enterprises.

In other places, the land was divided up between the sons (again, the daughters had to marry their money). It doesn’t take many generations for a large but finite area of land to be divided and divided until the people are peasants eking out a meagre existence on tiny blocks of land, with the bright lights of the city beckoning.