Fen for yourself

Harmony is no easy state to achieve on a bicycle. Usually the road is too rough, too crowded or too uphill. That gentle breeze caressing your face when you are standing still becomes a howling gale as soon you try to cycle into it. Likewise, an impressionistic haze of mist can transform into a cyclist-battering rainstorm. And the more you struggle against inclement elements, the greater the squeaks and clunks of complaint from the bicycle. Man and machine in discord.

Harmony is no easy state to achieve on a bicycle. Usually the road is too rough, too crowded or too uphill. That gentle breeze caressing your face when you are standing still becomes a howling gale as soon you try to cycle into it. Likewise, an impressionistic haze of mist can transform into a cyclist-battering rainstorm. And the more you struggle against inclement elements, the greater the squeaks and clunks of complaint from the bicycle. Man and machine in discord.

So to be bowling north along a country lane where motorised traffic is as rare as an incline, under a sky as broad as the Great Ouse is long, is close to Nirvana.

Nirvana is not a name you see on the map. Most of the place names in northern Cambridgeshire and the northwestern part of Norfolk have more to do with applied mathematics than pure serenity. On this 50-mile ride, you pedal along Twenty Pence Lane and pass close to Hundred Foot Drain and Six Mile Bottom, locations linked by some opaque formula that must surely involve Quarterway House.

The map of the Fens looks like a big, elegant exercise in geometry. Contour lines are thin on the flat ground; the northern part of Cambridgeshire that stretches into Norfolk is the closest that England gets to the geographically impossible geometric concept of a plane ­ a perfectly two-dimensional surface. (This quality also helps to makes cycling easier.)

But there are plenty of other lines, many implausibly straight. A Roman Road marches north from Cambridge, matched mile for mile by the 19th-century railway. Arrow-like dykes and ditches slice randomly, while between the finely named Landbeach and Waterbeach the Ordnance Survey map reveals an equilateral triangle comprising the three runways of an old airfield.

Ten Mile Bank is a stretch that meanders in graceful parallel with the curves of the Great Ouse. As you cycle through this hauntingly beautiful landscape, you might start feeling in harmony with this corner of the world. Indeed, the idea of spending a week on the waterways at an even slower pace aboard a boat may seem just the way to feel more in touch with nature. Yet little of this glorious landscape is natural.

Attempts at draining the marshes and bogs of eastern England began in the Bronze Age, and the Romans dug Britain's first canal in Cambridgeshire in the First Century AD. Only when the Dutch were called in during the 17th Century did the present extent of rich farmland emerge from the swamps.

The journey begins in picture-postcard land, with a winsome pair of villages named Histon and Cottenham. Gradually the ground flattens and the road straightens, with a beacon slowly rising in the distance: the incredible bulk of the Cathedral Church of the Holy and Undivided Trinity of Ely.

The cathedral's greatest strength is the intricate decoration. From Saxon origins, the Norman construction has been bolstered (usually through structural necessity, ie collapse) by Early English Gothic, with Romanesque and Renaissance touches.

Latterly, Ely has become Fenland's Clapham Junction, with a spiral of railway tracks adding an extra tangle to the roads and waterways. The ride north takes you parallel to the Great Ouse and the main railway line, past Littleport and on to those delicious curves of Ten Mile Bank (the name refers both to the dyke constraining the river and to a village half way along).

A feat of engineering to match Ely Cathedral awaits at Denver Sluice, the climax of the intricate web of artificial waterways that has developed over the centuries. Where the Great Ouse and the River Wissey meet the Old and New Bedford Rivers, a formidable collection of locks, gates and sluices aims to protect against flooding and coerce the waterways to wash away with the tide that makes incursions even this far inland. You can consider the scale of the challenge over a drink and a meal at the handy waterside pub, the Jenyns Arms.

A final hour's gentle pedalling takes you to King's Lynn, where the architecture has more in common with Bruges than Britain. Allow plenty of time to explore the relics of the Golden Age of this Hanseatic masterpiece. Stay overnight, check out the wind direction and map out the next day's journey on the level.

Tourist information: Ely (01353 662062), Downham Market (01366 387440), King's Lynn (01553 763044). Ely Cathedral (01353 667735) opens 7am-7pm daily in summer. A new network of circular walkways, cycleways and bridleways around the western Fens opens this year.

Getting there: Cambridge, Ely, King's Lynn and intermediate stations are served by West Anglia Great Northern trains. Call 08457 48 49 50 for details of times and fares. Bicycles are carried free of charge, with a few restrictions on rush-hour trains.