Imagine clambering aboard an aeroplane in London bound for Beijing. In just ten-and-a-half hours, your jet-propelled metal cocoon will have carried you more than 5,000 miles en route to the Chinese capital. Now imagine bedding down for the night, awakening bright and early the next morning, lacing up the walking boots and strolling back home to the UK, alone and unaided, through some of the most volatile countries on the planet (Belgium in January; a nasty, nasty business, let me tell you), and minus the crow's advantage of travelling the most direct route. So, add another 4,000 miles onto the 5,000, slow down the average speed from 450 mph to four, and you're looking at a journey that will take three to five years to complete. Yes, the margin for error is as great as a hamster's life, a simile that achieves precisely the opposite effect I intended.
