'In my youth,' said a Grand Union Canal worker, 'we would do anything in our power to prevent pleasure boats, and we would make it pretty plain to them. The boatmen regarded them as a nuisance, that's all. The idea of people using the canal for pleasure didn't seem to occur to us then.'

And why should it? To him, it would have seemed as daft as playing on the railways. He was being quoted in a waterways magazine of the 1970s, so when he was a young man in the 1930s, his canal between London and Birmingham was still very much a commercial transport artery. In October 1934, the Duke of Kent opened the 21-lock Hatton flight - nicknamed the 'Stairway to Heaven' - whose giant onion-shaped paddle gear so taxed me a few days ago. It was part of a 500,000-pound upgrade to the canal between Braunston and Birmingham. Someone in government believed even at that stage that this canal was viable enough to foot the bill. It wasn't of course, and all that remains are miles of concrete piling - curious 1930s concrete that weathers so redolently of the faux optimism of that decade - and overbridges whose design ominously presages that of the first motorway bridges.

In my own youth in the 1970s, one of my first trips on a narrowboat was through Stoke on Trent where I felt an intruder among the working barges then still moving great loads of finished china between various potteries. By then this was an exception and even when the old canal worker was a youth many canals were on the verge of dereliction. These days no one bar a hopeless romantic would advocate the use of England's canals, with one or two exceptions in the North-East, to move goods around. For that purpose they have been killed off by the very things James Brindley built his first canal to replace - roads.

Of course the coming of the railways less than a century after Brindley cut his first sod had a huge impact on England's inland waterways. But commercial traffic continued on many of them either in competition or in uneasy co-existence with the railways. No, it was the arrival of the motor lorry running on metalled roads that did for the cut. Traffic declined dramatically after the First World War, and when all commercial transport was nationalised in 1947, canals had but a small voice. In the 1950s, reasonable arguments to widen the Grand Union still further to take barges of up to 700 tons, for example, were drowned out by the cries of acclaim for the new in thing - motorways.

When the British Transport Commission, set up by the 1947 Act to co-ordinate and en passant cross-subsidise road, rail and water, was finally cremated in 1962, British Waterways arose from the ashes and immediately recognised two things: one, the value of canals for leisure and, two, the need to keep canals as an integrated waterways system to enhance that amenity value. It's taken BW nearly 40 years to throw off all the vestiges of the BTC antagonism towards leisure boating and become purveyors of pure pleasure, but it has and is making a pretty good fist of it.

There are those who criticise British Waterways, and some with good reason, though many complaints come from British Waterways being forced by the government obsession with the soi-disant competitive tendering to use outside contractors for work it could adequately do itself. And there are those on the cut who resent the curtailment of their free and easy lifestyle. But they are a little like the early users of the internet who resisted any attempt to police its content.

With so many people and so many boats using potentially dangerous equipment on the waterways, British Waterways would be mad not to introduce new rules and regs. Think of the outcry when anyone dies in a lock, for example - a mercifully rare event - though the outcome may be the death of journeys such as mine. A lockkeeper helping me through a staircase on the Leeds and Liverpool Canal what seems so long ago asked me if I was working the boat on my own. I said I was and he said, technically, I was breaking a British Waterways bylaw that states all boats must have adequate crew. What's adequate, I asked, and he laughed as he waved me on my way.

Pleasure boating on the cut in such numbers as today - around 25,000 licensed craft on the waterways - is a phenomenon of the past 25 years but its pedigree goes back a century or so. Popular accounts of improbable journeys were published in the early years of the twentieth century by such folk as E. Temple Thurston and the magnificent P. Bonthron, who took his Daimler-powered motorboat, Balgonie, to places a motorboat had never been before. But it was George Westall in the 1920s and in particular L.T.C. Rolt in the 1940s who really opened the public's eyes to the fun that can be had messing about on the cut.

It was enthusiasts such as Rolt who formed the Inland Waterways Association in 1946 to lobby for the preservation of canals for both pleasure and, haplessly, commercial use. Well, one out of two ain't bad. It's certainly better than none, which is what might have happened if some transport chiefs of the 1940s and 1950s had had their way. But they reckoned with people power, effectively marshalled by the IWA and many burgeoning canal preservation societies.

Before reaching the Stairway to Heaven, my journey aboard Stealaway last week has taken me over three of the most sensuous and stirring waterways of my entire trip, through wooded cuttings thick with foxgloves and past straggling hedgerows full of dog-rose brambles in full bloom, the delicate pink, white and petals sometimes blown by an unseasonable wind to cover the cut like a carpet. Thirty years ago my route from the Severn at Tewkesbury to the Grand Union at Kingswood, southeast of Birmingham, would not have been possible. But the restoration of the Lower and Upper River Avon, and that of the southern section of the Stratford on Avon Canal, by volunteers and other enthusiasts pursuing the pure pleasure of leisure boating created the pace that so many others have followed.

British Waterways likes to boast that we are currently in a second canal age when more miles of cut and other navigable waterways are being opened or considered for opening than in the original years of 'canal mania'. But there is a big difference; this time it's for pleasure not profit, and that the environment that the canal passes through, and indeed helps create, is as important to its purpose as the cut itself.

One of the schemes proposed - the driving northwards of the Upper Avon Navigation from Stratford to Warwick, so fulfilling the original seventeenth-century plan - is typical of today's approach in not only providing new routes for boaters and enhanced opportunities for walkers, cyclists and even anglers, but also in devising imaginative habitats for wildlife by building such stuff as silt banks, and planting reeds and sedges, hedges and hardwood copses, to encourage flora and fauna back to areas depleted by urban growth.

If this link is ever built, and the omens are good, then I, for one, want to be at the head of the queue to sail it. Although the still waters of the cut are intimate and charming, there is something exhilarating about the live water of a river. I loved how Stealaway battled against the flow on the Avon. While weirs and locks try their best to tame the natural exuberance of rivers, they are not always predictable. Just 36 hours of summer rain, boaters are warned, can turn the normally peaceable Lower Avon into an unnavigable raging torrent. And worse: chatting to the lockkeeper at Evesham, where the Upper and Lowers Avons meet, he recalled the fearsome flash flood of April 1998. He pointed to the first floor of his remarkable wooden A-frame house ('came from Sweden in a flatpack 27 years ago') that is perched 10ft above an old lock chamber:

'We were trapped upstairs in pitch black,' he said. 'The water shot through, blowing out windows and doors. We had a narrowboat stuck up in those trees beside the weir.'

'How did you get out,' I asked.

'Well, as luck would have it, the SAS were on exercise nearby and they came to our rescue. There were six of them, all with blackened faces. They'd just got the missus out of our bedroom window when they said they had another emergency.'

'Another one!'

'Yes, there was an old dear in a mobile home across the river that was in danger of being washed away and she was refusing to budge without her pets. So the SAS boys shot off in their rubber dingy to get her, then came back for me. As I sat down in the boat, the old dear screamed at me: "You're sitting on my parrot." Apparently, the SAS has just grabbed it out of the cage and shoved it in a shopping bag.'

'Was the parrot OK?

'Well, put it like this: he'd never talk about it.'

· Mike Holland is writing weekly online dispatches from his canal journey around England. Thanks to the wonders of wireless technology, you can email him at michael.holland4@btinternet.com.