Inside Britain's deepest dry valley

Devil's Dyke, West Sussex I carefully descend the muddy paths down to the bottom, where it is strangely quiet

The small car parks and lay-bys are full, and cars are already beginning to line the sides of the road. The morning sunshine has drawn the crowds to this beauty spot on the top of the South Downs, with its panoramic views of Brighton and the Channel to the south, and the Sussex Weald to the north. A crow calls from the black skeleton of a tree, making itself heard above the noise of traffic and people.

I follow the main path uphill, passing dog walkers and families with running, laughing children, and cut across the white, frost-covered grass and through a gap between the trees. This side of the valley is in cold, dark shadow, but the other glows golden in the sunshine. I carefully descend the muddy paths - still frozen and slippery - down to the bottom, where it is strangely quiet.