Country diary: lowest land in Britain is unsettling in the gloom

Holme Fen, Cambridgeshire: The trunks tangle back from both sides of the track, like wiry hair, their bark papery. Packed dense, this makes the forest look grey and odd

Britain's highest highpoint is Ben Nevis. The lowest highpoint, if you like, is in what was Huntingdonshire: Boring Field, an old county top, at 81m above sea level. But hereabouts too is a mountain's true inverse: the lowest lowpoint. The road to Holme Fen protrudes, like a fat plank thrown over a bog. You could fall off it if you're distracted. I am, first by the red kites: they're everywhere here, black wraiths cruising on dog-leg wings. I count nine within a kilometre. Then two herons, side by side at the side of the road and unbothered by it, those stripe-masked faces like strange little highwaymen.

It's early, and the morning is feebly painted in winter colours: black fields full of rain, brown water, grey sky. It should be light by now but it isn't. I turn on to the fen track and suddenly there's red: the lights of a railway crossing, then the train blurring noisily beyond it. Beyond that, in a thicket of woodland, is the lowest land in Great Britain.