Why are some dreams so vivid but also so difficult to recall when one wakes? All I can remember of last night’s dream is sitting in the sun on a hillside while flocks of little blue butterflies gyrated around me.

But I know where those Chalk Hill Blues used to dance, skimming the dry thin grass on a hill over-looking Caterham valley. It was a favourite destination of mine and my friend Jenny, when out for a bicycle ride. We cast our bikes down by the stile, climbing over onto the white path which crossed the steep meadowland. We searched for arrow heads for there were bands of flint running through this chalk hill. I don’t think we ever found any. But I do remember the springy feel of walking there as though the hill itself bounced under our feet. Male Chalk Hill Blues are pale, spring-sky blue, their wings…