A night run of at least 30 miles from Guildford to London had seemed a good idea earlier this week. Today – at home, in the warm and dry, surrounded by food – it seems a good idea. Crossing the M25 at 11 o’clock last night, having negotiated 15 miles of the North Downs Way and soggy Box Hill – all in the dark – with another 15 miles of pavement-pounding to go, the whole ordeal seemed anything other than a good idea. This was stretching the boundaries of fun.

It started easily enough. (It always does!) The pavements of Guildford gave way to the sand of St Martha’s Hill, and the mud of the North Downs Way to Westhumble thereafter. The world is, naturally, a different place by night. Views are replaced by twinkling lights; North Downs Way car parks are used for alternative purposes; the familiar is unfamiliar. For large chunks of our journey, our existence shrunk to the milky beam cast by our head torches. The pace of our trio was deliberately slow, partly due to the greater care necessitated by darkness, partly due to the distance ahead.

A grind up steps to Box Hill, a sparkling view of Dorking, then a fortuitous descent to Mickleham. Stane Street, a classically-straight Roman road, went north and east, flinging us over the M25 to Epsom Downs. It was then a very long way from Epsom to Streatham on a route that desperately lacked inspiration: Ewell, North Cheam, Morden, Mitcham and Streatham – places not known for their prettiness. There were dodgy looks and sporadic abuse. The only benefit from such a route was the 24-hour petrol stations. Marathon distance passed, then the psychological milestone of 30. Bodies began breaking down. Running resembled limping, while Duncan went down with jelly baby poisoning in Mitcham. With a mile to go, I pressed on alone, through 33 miles, through six hours, through 1am. This had been no race, but there are few better finish lines than your own front door.

Route here