The National Cycle Network, chosen as a landmark project to celebrate the millennium, was funded with £42 million of Lottery money and consists of 5,000 miles of both off-road and traffic-calmed routes in Britain and Northern Ireland, as well as unmarked routes along mostly quite lanes. By 2005, a further 4,000 miles will be added and the network will be complete. This network is to do much of the work of making the UK a place in which cycling is something less than insanely dangerous and, hey, even health inducing.

For those of us who daily suck down fumes as we cycle behind buses, waiting only for the moment when some clown in a white van opens his door and projects us into orbit, the growth of this network, though not in itself enough, is no bad thing.

That said, it is inevitable that the National Cycle Network will primarily be a leisure facility. Most of it runs through beautiful rural districts that deserve to be savoured at a relaxed speed. The network has been designed by a small charity called Sustrans, which is short for Sustainable Transport.

Typical is the new 200-mile section opening in early June called the Coast and Castles Cycle Route. It starts in Newcastle, runs along Hadrian's Wall for a stretch, then up the wonderful castly coastline of Northumbria, up and down the Tweed valley before reaching Edinburgh.

This is one of the safe, attractive routes that should ideally be used in conjunction with the integrated public transport system. Which would be nice if there was one. True, many of the routes devised by Sustrans have rail connections. But that is not enough and the cumulative effect of cycle-unfriendliness on the railways is that many people feel obliged to transport their bikes by car, which is no way to carry on.

But that's enough carping. Sustrans' work in negotiating with 400 councils, landowners, businesses and what can only be described as the British Railways Board to push cycle routes through this patchwork quilt of a multi-owner-occupied kingdom deserves a great deal of credit.

Sustrans also deserves praise for setting up a pilot project called Safe Routes to Schools and aimed at doing something about these dreadful figures: 60% of children cycle to school in Denmark compared with 2% in Britain.

Thanks to Sustrans and the city council, it is now a delight to cycle in and around Birmingham, along the industrial-archaelogical sites that line its towpaths. It's even more of a pleasure to roll into Glastonbury along the Willow Walk, a verdant artwork created by Katy Hallett.

The charity has also acquired more than 200 miles of former railway routes and incorporated them into the network. It's heartening to know that a covenant ensures their possible future use as railway corridors, though, if that covenant is taken up, it's hard to know what will become of the millions of us who will be cycling along them in years to come.

All of these former railways have gentle gradients which make them suitable for cycling families with young children, though not exclusively so. When I cycled from Barnstaple to Plymouth last year along the newly-opened cross-Devon route, much of which was along a disused railway, there was purple scabious around my ankles and lilac brushing my cycle helmet. If I had been any more relaxed, I would have crashed into the bushes.

White Rose Route: Hull to Middlesbrough. 123 miles, easy/moderate

Route 65 presses north alongside the Ouse, then through the quiet country lanes of the Vale of York, before rising up into the foothills of the North Yorkshire Moors. There's money in those hills, the kind of cash that demands that pubs in the vicinity have impressive wine lists and patrons who speak in that singular dialect, Yorkshire posh, just like William Hague.

It was a lovely ride, and so well signposted that I barely needed to consult my map.

I picked up the route just north of York railway station last Saturday on a sunny spring morning. Rowers were lifting their craft into a sparkling river and gardeners had emerged from a row of semis to tend the hanging gardens that step down to the Ouse.

I swept on through the water meadows alongside the Ouse and past the leisurely dog walkers of this contented, cycle-friendly little city, and then under the seething outer ring road. Then I left the cycle path that runs through fields and joined a country lane near Skelton, where an evocative weather vane of cyclist and dog marked the transition.

At nearby Shipton, two railway carriages have been fitted up as restaurant and hotel, but I was too busy pedalling off a thumping breakfast to patronise the Sidings Hotel in all but the most notional sense. From York to Easingwold, it's flat terrain, and consequently a little windy for the wobbling cyclist on even the stillest day.

Just on from the Sidings Hotel lies the baroque pile of Beningborough Hall, a nice place for a contemplative wander if you have £3.50 about your person. "Explore Victorian life in the Laundry and Potting Shed," advised the blurb , but instead I roamed the soothing gardens and the collection of more than 100 portraits from the National Portrait Gallery.

They really know when to mow village greens in this part of Yorkshire. Daisies, like white Smarties sprinkled by a god with fine attention to detail, glittered at me from one such green at Newton-on-Ouse. More ruthless gardeners would have cut that green of all such interest.

There was time to consider such details since this was an easy cycle. At Easingwold, though, things changed. Inclines got steeper. I was whisked, thanks to Sustrans' route, into the village's Millfields Park, opened by the mayor only last year, and then through a rinky-dink housing estate, complete with mock-Georgian carriage lamps. The ups and downs of this portion were a surprise to me.

At Newburgh Priory, I saw triangular sign warning of looming ducks. It's so peaceful hereabouts that damp birds are the most prominent of traffic hazards. Mind you, they were quite burly ducks.

At Coxwold, a twee village on a hill, I sank two litres of mineral water, only pausing to emit grateful noisy sighs that seemed to affront the genteel patrons of the adjacent Fauconberg Arms. At this village, Sustrans splits the route in two - a gentle low road direct to Kilburn, and the high road, which I took, that pushes deeper into the hills of the Moors. By the time I reached Byland Abbey, crossing hills and dales, I had sweated most of the water on to my skin surface, thus attracting all of the local insect life.

It was time for lunch. The Abbey Inn, opposite the abbey ruins, is recommended by Egon Ronay and, to a lesser extent, me. It has a restaurant, a good wine list, a delightful garden and a very small bar. I was dehydrated and in urgent need of the sustenance that only a poached salmon sandwich and a pint of Black Sheep bitter can supply.

Fed, watered and abluted, I hit the road again. The White Horse, sculpted into the moorland hills, had long been an uncertain friend, playing peek-a-boo with me as I rose and fell over the hills. At Kilburn, Sustrans offered me another choice: back down into the valley or up into the moors. It was at this point I realised that I urgently needed after-sun lotion, and so headed down towards civilisation. My arms were turning weasel red and so I customised a quick route to Thirsk railway station. I was, nonetheless, very much taken with Sowerby, whose avenues of limes and floral verges were everything they should be.

At Thirsk, it was race day. As I cycled along the road parallel to the the two-furlong marker, a steel band struck up something carnivalesque that spirited me on to the station. Watch out for that right-hand turn into the ticket office, though. It's a doozy. The rail journey from Thirsk to York passed without incident. It's worth recording that all the GNER staff I encountered both on this local service and on the mainline to King's Cross were properly solicitous for me and my bike. In York, I got the attention my arms so needed.

Where to visit: Beningborough Hall, Newburgh Priory (only open on Sunday and Wednesday afternoons), the White Horse at Kilburn, the ruins of Byland Abbey. Where to eat and drink: The Sidings Hotel and restaurant, The Facuonberg Inn, Coxswold. The Abbey Inn, Byland Abbey.

Thames Valley: London to Oxford. 97 miles, easy/moderate

I rode the Thames Valley Cycle Route from Putney Bridge to Windsor. If there were hills, my calves didn't notice them.

This was never, nor was meant to be, a cardiovascular work out. There were herons who sat on the Thames path near Molesey Reservoirs and blocked my way until the last possible moment. They flapped into the air with insolent laziness before settling fatly in my path once more. I felt sure they were the psychic equivalent of sleeping policemen. "Slow down! Slow down! You'll enjoy it more." That is what they would have said if they could have spoken.

Admittedly, I became embroiled in a little altercation near the Ferrari outlet on the Egham by pass, and the one-way systems of places like Kingston, Staines, Weybridge and lots of other identikit towns, jolted me from my reverie back into irksome reality. At these points, where a single slip can mean a 20-mile detour around Slough, the Sustrans map of the cycle route became hot in my hands. It proved very easy to follow, colourful, waterproof, and with smart inserts on how to get through commuter town centres without upset. The only problem with fold-up maps for on-the-go cyclist, to my mind, is that after a little bit of folding and unfolding, a tear always emerges at the vital corner. Much better, surely, to print the maps in little ring binders, as for example they have done with the Hayes London Cycle Guide. If I'd had a ring binder for a map, that whole Egham debacle, I am certain, could have been avoided.

As I cycled these 40-odd miles, I felt protected from the traffic roar all around me. Sustrans has created a route that is a miracle of calm, though north of Windsor there is not yet a quiet path through the dismal jungle of Heathrow buildings and motorways. But even along the Putney to Windsor stretch, 747s are always with us. Only they interrupt the serenity.

From Putney, the route took me along the Thames path for a little while, then nipped through Barnes's interesting collection of Toucan crossings and cycle lanes, before switching, delightfully, into Richmond Park, where it proved necessary to stop for the first of series of unhealthy snacks at Pembroke Lodge. A Toucan crossing, it turns out, is like a Pelican crossing for bikes. The park route forms a by-pass around Richmond. As a result, I missed one more English one-way system and Quinlan Terry's Prince Charles-approved retro riverfront development, for both of which, Sustrans, much thanks.

After Richmond Park, I rejoined the Thames and swept through Teddington, where Magpie was filmed. Then I fringed Hampton Court Park. I hugged the Thames path tight as we swept through the badlands of the commuter belt. I have watched my Ali G, after all, and know that the feud between the West Staines and East Staines massives means that they regularly get medieval on eachothers' bottoms and, perhaps, on those of passing cyclists.

This is an overdetermined corner of England, where heritage history does battle with a frenzied suburban aspiration and just about survives, but only thanks to the suburbanite need to express its collective Englishness through frequenting cream-tea joints and wandering through courtly fields to stately homes.

There was almost too much history to take in. I found Runnymede, for instance, too replete with suggestion: the Magna Carta Tea Room, on Windsor Road, for instance. Nonetheless, I rolled my bike deferentially through the meadows where King John met 25 rebellious barons and placed his reluctant seal on the articles that became the Magna Carta. I strove to feel what the Ameri can Bar Association felt when they erected the Magna Carta Memorial on a hill overlooking the meadows in 1957. Or what the government felt in 1963 when it gave over one acre of Runnymede to the US to commemorate the death of John F Kennedy. At the Kennedy monument in this little bit of America, I removed my cycle helmet.

After Runnymede, I stopped for a drink at the Fox and Hounds at Bishopsgate on the fringes of Windsor Great Park. This has a nice garden for a well-earned sit, and is a good place to reflect on the equestrian culture that thrives royally around here. Then I descended from the tranquil heights of Windsor Great Park to Windsor Castle, that jewel in the crown of multiple fudge concessions, gourmet coffee shops and souvenir emporia.

At the Theatre Royal opposite the Queen's pad, they are staging a new musical called Hard Times. Fudge-sated tourists and complacent locals mingled in the queues to hear the evils of Victorian capitalism expressed in easeful song. History has become harmless here and even our ancestors' sufferings are sold back to us for fun. I cycled on to the station, eager to leave.

Where to eat and drink: Pembroke Lodge, Richmond Park. Magna Carta Tea Rooms, Runnymede. The Fox and Hounds, Bishopsgate.

Cycling essentials

What to wear

· Loose clothing that allows freedom of movement is essential. Short, tight T-shirts, for instance, may look fetching, but they will result in an ugly sunburned rim in the small of your back. Trust me. Lycra, for some, is just the thing, though gentlemen who favour very tight Lycra shorts might do well to reflect that children and horses are easily disturbed by such sights.

· Waterproof tops and trousers are a necessity. They roll up small in your pannier and are extremely light. Forget them and it will rain hard and you will be very miserable. Gore-Tex is a good breathable material.

· Gloves. The wind and rain numb your knuckles, and if you take a tumble you are very likely to graze your hands. Gloves can help in both cases, though perhaps not knitted ones.

· Helmet. Most of the routes on the National Cycle Network involve tricky little on-road switchbacks during which white van men and boy racers will try to put you in casualty. A helmet will help frustrate them and, to my mind, looks quite stylish.

What to take

· Accessories. You will need a pump, a puncture-repair kit and a spare inner tube. The last is fundamental if you don't want to spend desperate hours hunting for a puncture on an old inner tube as dusk sweeps across the moors.

· Don't forget lights and reflective belts. If the weather turns, as it does in Britain, or you run out of daylight, these are essential, especially on dark country lanes.

· Drinks. Even when it's cold you will need to drink because you will dehy drate. Take a water bottle, preferably one that you can attach to your bike frame.

· Food. Cycling in Britain is hardly a gourmet experience and it's hard not to eat unhealthily, given the dictatorship of cream tea shops, real-ale boozers and fry-up devotees in our countryside. You might want to consider sandwiches, particularly those with a low likelihood of turning soggy during the morning. Bananas are good for energy.

· Sun-block is important if you don't want your arms, legs and - who knows - bald spot, to be red raw by the end of the day.

· The first 5,000 miles of the National Cycle Network opens on June 21.This is only half the story though. Sustrans, the charity coordinating its building, has another 5,000 miles due for completion by 2005 and needs more funding to continue the work. If you want to make a donation, you can become a Sustrans supporter through its website: www.sustrans.org.uk, by calling the information line on 0117 9290888 or by writing to Sustrans, 35 King Street, Bristol BS1 4DZ. Any donations made now will still be matched by Millennium Commission funds.