“We’ve lost so much,” says Mike Pratt, reflecting on Britain’s nature crisis. “We’re getting to the point where if we’re not careful, children in the future won’t know what a hedgehog is. They won’t have encountered one.”

Pratt, the chief executive of Northumberland Wildlife Trust, is speaking on an unseasonably sunny, calm, blue-skied December day surrounded by ruggedly beautiful, spirit-lifting countryside.

You look around at the dramatic Simonside Hills, or stunning moorland, or bucolic fields of grazing sheep and you don’t immediately see crisis. But, as ecologists, environmentalists and politicians have highlighted, the UK is one of the most nature depleted countries in the world.