ENGLAND has one of the largest canal networks in the world. Wales and Scotland also have canals but only a few. Today, our 2,000 miles of canals and rivers flow through cities, past homes, alongside offices and into the countryside, bringing leisure opportunities to millions.

From boating, fishing, walking and cycling, they offer a range of activities. Their history, however, reveals a very different function.

Most of our canals were built 200 years ago, but their history dates back to the Romans who built our oldest canal, the Fossdyke Navigation.

Before 1700, most British inland waterways had been constructed by aristocratic landowners to carry agricultural products in southern England. However, in that year a new waterway opened that was radically different.

The Aire and Calder Navigation, linking Leeds to the sea, was built primarily by textile merchants and coal owners who saw a better transport infrastructure as vital for their trade.

The 18th century saw a big surge in canal building and the dawn of a new “canal age.” Canal construction became a speculative industry. By the 1770s many of the original promoters of canal construction had become so wealthy, that they were able to buy large country estates.

This canal mania led many to imagine that a canal alone would create wealth. Despite several failures, there were many successful projects, and the volume of goods carried by canal increased rapidly, enabling Britain to become the leading industrial power in the world. By 1850, around 4,800 miles of inland waterways had been constructed.

More river navigations were built by northern merchants in the first half of the 18th century, strengthening the position of established industrial towns and creating new ones like Liverpool and Manchester.

It was the success of these early industrial navigations, together with his visit to the Canal du Midi, which prompted the Duke of Bridgewater to build his canal in 1761.

He alone financed the project, and because of his social position, the canal became a magnet for visitors — both from Britain and abroad. His example certainly aided the promotion of canals, and their effect on Britain’s economy was dramatic.

When the Duke’s canal opened from his coal mines in Worsley to the centre of Manchester, the price of coal in the town was halved overnight.

The next 20 years saw the formation of most of Britain’s most important canals, set up by merchants, members of the aristocracy and bankers, but particularly by coal owners, textile manufacturers and pottery barons wanting to open up new markets.

Although the use of floating water channels can be traced back to the days of the Roman Empire, aqueducts were not used for the passage of boats until the 15th century. The idea of a “canal in the sky” was ridiculed initially both by engineering sceptics and canal builders themselves.

Early canal builders did not relish building aqueducts because the weight of the water meant they needed a substantial masonry structure to support it. These problems were eased when they started using cast iron troughs in the late 18th century.

The two great aqueducts of today, Edstone in England and Pontcysyllte in Wales were both constructed using cast iron water troughs.

As part of the construction of the renowned Pontcysyllte, ox blood was added to the lime mortar used to bind the masonry together. This followed the ancient superstition that the blood of a strong animal would strengthen a building.

The success of the waterway system, and the industries it supported, had a major effect on Britain’s economy, creating the wealth necessary for the country’s dominance in the Victorian era.

However, waterways were essentially local in character — financed and built by local people, and their greatest effect was upon the communities through which they passed.

It was the decline in traditional industries after each of the two world wars that put an end to most commercial use of canals, but they retain unique historical importance.

They are home to over 2,700 listed structures, 50 scheduled ancient monuments and four Unesco world heritage sites. You can view historic engineering projects on a grand scale, like the Pontcysyllte Aquaduct and Anderton Boat Lift.

Canal construction involved huge feats of engineering and the back-breaking work of tens of thousands of “navigators” or “navvies” as they were known.

The canals formed the nation’s industrial arteries and transported vital goods essential to the burgeoning industrial revolution.

When freight declined as a result of railway and road expansion, the canals fell into disrepair. Thankfully, our waterways have become treasured places, where people can relax, reconnect, rediscover history and observe an abundance of wildlife.

Until 2012 the canal system was managed by a public corporation, British Waterways. Recent Tory governments were keen to privatise the system, but in the face of protests, including from Unison which represented members working for British Waterways, a compromise was achieved, and management devolved to a charitable trust, the Canal and River Trust.

In Scotland, however, the management of canals remains in public ownership. The trust cares for a 2,000-mile-long green-blue ribbon that connects hundreds of wildlife habitats, helping everyone to get closer to nature wherever they live. It is responsible for making sure that 2,949 bridges, 1,582 locks and 280 aqueducts are open and ready for use all day, every day

The great thing about canals is that they are easily accessible, whether you live in a town or the countryside. Taking a narrowboat on a canal, a stroll or a cycle ride along the towpath, are enjoyable and relaxing experiences.

Today our canals are havens for wildlife. They hold many species of fish, and at weekends you can see rows of determined anglers, crouching immobile under umbrellas, staring at their floats, hoping for a bite. Roach, pike, and carp abound but also rarer eels and bullheads.

Waterbirds flourish, too: coots and moorhens, mallard and tufted ducks, mute swans and even the elusive kingfisher. In the summer months, you can even spot terrapins sunning themselves on fallen tree branches, although these are not native but have been released from captivity. Insects like dragonflies and damselflies are abundant too.

My local canal — the Grand Union — will take me into central London or as far as Birmingham. Years ago, it used to be a quiet backwater with little traffic and few boats moored.

But in recent decades it has become a thriving waterside community of not only narrowboats, some beautifully kept, with hand-painted decoration, flower gardens and solar panels but also of DIY hulks, more reminiscent of junk containers.

Their proliferation is a result of the acute housing shortage, particularly in London, as they offer a cheaper alternative to renting or owning a house.

The canal system is a precious heritage for our children, and their children too, so that they can connect with our history and enjoy its rich legacy.