It is true that some land that is now urban or used for grazing was more once intensively farmed (especially eg in the highlands where most agriculture is sheep farming). But I think the amount of land devoted to crops, and certainly the kind of intensive growing that leaves little room for wildlife is a more modern invention.
I would guess that land devoted to agriculture (maybe except for some kinds of grazing) probably peaked in the 20th century, perhaps during or shortly after the war when food imports were harder to come by.
https://en.wikipedia.org/wiki/Forestry_in_the_United_Kingdom...
You don't need natively forestry so much when you've a subject neighbour to pillage.
Did you read past the title? It's not supposed to be concerning.
> The world produces more food than ever, but the amount of land we use is now falling. This means we can feed more people while restoring wild habitat.