Until a few years ago, you could be climbing any chalk down in Southern England. Trails lead up from a council estate, past a recreation ground. On the slopes above, young men with tattooed arms walk their dogs. The grass is like an old rug, woven with wild flowers, cabbage whites and meadow browns. Then the next step you take is empty air.

Few cliff tops drop away so dramatically as this corner of coast where the North Downs are truncated by the Channel. Wave erosion caught the escarpment on an upswing: the sudden panorama is enough to make the heart miss a beat. Sea-level is only some 350 feet below but you can't test the overhang. Clouds could be a few feet distant, or a few miles. Even the chalk underfoot seems to shift.

On Shakespeare Cliff, just west of Dover, vertigo has a good precedent. In October 1604, at the time Shakespeare was probably writing King Lear, his company, The King's Men, visited Dover. In the tragedy, the Earl of Gloucester, blinded for his loyalty to Lear, meets an itinerant beggar 'Poor Tom' and asks him 'Know'st the way to Dover?'.