The Big Read - England: Go West, young man

Nicholas Crane and his teenage son cycle out of London and follow rural byways all the way to Devon

The plan was simple enough. We would cycle from London to Devon. From the city to the sea, sleeping under the stars, wherever we could find a spot to spread our bivouac bags. It would be a father-and-son adventure. Kit is 16; I am old. Neither of us owned suitable bicycles, so Kit rebuilt the decrepit 30-year-old Claud Butler he'd extracted from his grandfather's garage a couple of years earlier, and I bought an '80s Raleigh on eBay.

We left home in the half-light of a midsummer dawn. Kit's bike broke first. About 450m from our front door, the "Claud" announced its unsuitability to the task ahead with a metallic crunch that pitched its rider onto the crossbar. A wrongly routed gear cable had caused the rear mech to jam. We spread the tools on top of Primrose Hill (breakdowns are like picnics; best enjoyed with a view). It was 5.30am. Below us, London still slept, the tip of the Shard lost in low cloud and the sun finger-hauling itself over the eastern tower blocks.

Ten minutes later, with oily fingers and reignited brio, we were off again, flying through hushed streets towards a narrow gate in Little Venice. We had two maps. The first, supplied free by Transport for London (TfL), showed us how to leave the city without using a road. The second, from Sustrans, would guide us onward to Devon using the National Cycle Network (NCN), a combination of bike tracks, tow paths and rural lanes.

The TfL map led us to the Grand Union Canal, in the shadow of the Marylebone flyover. The bikes rolled from tarmac to towpath, through an urban portal to join a reflective thread of water that uncurled through the metropolitan chaos of streets and buildings. As our tyres whispered past the needled spire of St Mary Magdalene, a rainbow striped the sky.

According to our TfL "Escape Map" we'd be with the Grand Union all the way out of London. It was one of the most extraordinary bike rides I've had in England. We cycled past a gas works, the multiple rail sidings of the "North Pole International Depot", Wormwood Scrubs prison, various industrial sites, a cemetery and a golf course. At one point, we were just 1.5km or so from Heathrow airport. All that, with a foreground of dappled water, herons and twitching reeds. Towpath pedalling imposes a sedate cadence on cyclists; one misjudged swerve and you're in the drink. Provisionally, it also prevented me from being left behind by an over-eager 16-year-old. At 9am, we reached the cast-iron aqueduct that marks the border of Greater London and rode off the edge of the TfL map, beneath the M25 and past our first arable field.

The canal took us to Slough, where it terminated in a thicket of bulrushes beside a builders' merchant. The roads were still quiet, so we postponed joining the National Cycle Network back-roads and took the old Bath road west to Reading, where we got so lost we had to use an iPhone compass and the advice of a prison officer leaving his night shift, keys a-jangling, to unlock the mysteries of the maddening road system. Kit spotted the small, blue adhesive NCN sign, and we turned for a second time that morning into a parallel world. Route 4 promised to guide us the whole way from Reading to Bath, mostly off-road.

For the next few hours, we were on the towpath of the Kennet and Avon Canal as it stretched westward through sunlit boughs and meadows. A pub appeared at the right moment for lunch and a tea shop popped up behind a hedge in the afternoon, just as my legs were beginning to scream for scones and tea. We reached Newbury too late for the shops, and were resigned to skipping supper when the teenager scented a faint whiff of burgers on the breeze, and was gone with a clacking of briskly shifting gears. So we cycled into the setting sun, back pockets bulging with fast food, and unrolled our sleeping bags on the crest of the Downs. According to the gadget on Kit's handlebars, we'd pedalled 130km since leaving home.

Next morning, damp with dew, we flew at Tour de France velocity down to Hungerford ("Appropriate name!" yelled the teenager) and ordered a pair of full English breakfasts at a tea room called the Tutti Pole. I was ready to linger till elevenses and try the cakes but my companion - having inhaled a full English in one breath - was eager to pedal.

Route 4 led us out of Hungerford on a thin lane framed with fluttering beech leaves. It was a wonderful day to be on a bike. You could feel the warmth of summer through the handlebars. We were climbing over the swelling roof of Wessex, over the watershed between eastern and western England; leaving Berkshire and entering Wiltshire. Vignettes from an earlier England drifted by: the sails of a distant windmill; a man opening a lock gate; the village of Great Bedwyn, with its ruddy brick cottages and Dickensian bakery. An outstanding lemon-drizzle cake was available further on, in the tea room attached to the Crofton Beam Engine.

In canal history, Crofton is up there with the Anderton boat lift and Pontcysyllte viaduct. Crofton's steam engines were built 200 years ago to pump water to the highest point of the Kennet and Avon Canal, as it ascends lock-by-lock over the crest of the 137m watershed separating Reading from Bristol. The engines are kept in working order by a team of volunteers. Every push rod and brass dial glints with mechanical virtue. In contrast, my bike had developed a creaky crank ("Sure it's not your knees, Dad?"). With minutes to spare before closing, we made Devizes, where the proprietor of Bikes 'n' Boards applied his crank tool to my bottom bracket and vanquished the creak.

We woke in long grass somewhere in west Wiltshire. Kit said, "Let's go to Bath." So we took the towpath west into wooded hills, riding beside a line of moored narrowboats roofed in flowerpots and firewood, almost to the centre of the city. Unshaven, unwashed, we went to the Roman baths and stood on a lip of footworn sandstone fighting the urge to dive in, fully clothed. You have to travel from London to Bath under your own steam to discover how far apart they are. I understood the pleasure Roman travellers must have enjoyed as they sank into the soothing, warm waters. The thought alone was enough to induce faintness.

Bath was a turning point in our ride, from westward to southward, and from easy to eye-popping. No gentle towpath led on to Devon. Instead, there were country lanes that climbed abruptly into Somerset, a county of topographical extremes. In driving rain we hauled ourselves over the alpine foothills of the Mendips and then - after a welcome night in beds at a friends' in Bruton - found ourselves rolling painlessly across the Somerset Levels, a fenland of pollarded willows and long, straight dykes called rhynes. Muchelney Abbey appeared through a veil of drizzle. We were tired, hungry and grimy, and the old monastery offered shelter, coffee and biscuits. If Henry VIII hadn't levelled the place in 1538, it would be one of the wonders of the West Country. But the stone ground plan of the monastery is still etched into the grass.

The Somerset Levels ended with a wall of hills more than 180m high and a road like a plank leaning on the sky. As soon as Kit disappeared from view, I climbed off the bike and pushed. The top of this climb was an airy ridge marked on the map as Windwhistle, and this is where we joined a Roman road to swoop from the cloud to the sunlit shores of Devon.

The National Cycle Network had another treat for us at Axminster: a new cycle route from the edge of town all the way to the lapping waves of the English Channel at Seaton. It was a good moment, sitting on the seafront with fish and chips before a still, blue bay. London seemed far away; thousands of pedal revolutions in the past. We pottered on that evening, through the old smugglers' village of Beer, to flower-decked Branscombe, then up again to Salcombe Regis as dusk snuffed the sunlight from the woods. The descent into Sidmouth was so steep that the brake blocks melted.

After a night under the stars above the English Channel, we picked up Route 2 of the National Cycle Network, which took us along an abandoned lane beside the River Otter to a disused railway track that sneaked into the backdoor of Exmouth, where we carried the bikes onto the passenger ferry across the mouth of the Exe estuary.

South Devon basked under a Mediterranean sun.

The English Riviera resorts of Dawlish, Teignmouth, Torquay and Torbay seemed more foreign than usual, with their piers and promenades and stuttering traffic. The final night in sleeping bags was spent in the deep blackness of moonless Devon countryside, and at dawn on the sixth day out of London, we pedalled into Totnes, parked the bikes outside the Royal Seven Stars Hotel, and ordered two breakfasts. With extra toast.

©The Daily Telegraph, London