How did your river journey begin?
After the Mountains series went down well I wanted to put together a history of landscape. However, that’s a huge subject so we turned our attention to what made our landscape – water. So from the mountains I went to the valleys. What fascinates me is that our rivers are how man truly interacts with the wild. They’re corridors of eternal nature, because rivers will be there long after we’ve come and gone.

How has that interaction changed over time?
For 3,000 years there was an unchanging relationship between man and rivers. They were originally great paths through a landscape that would have been almost impenetrable. In medieval times they were extraordinary highways, where now obscure inland towns were built to benefit from not only trade routes, but also the drainage and health capabilities of the water. But in the last 300 years there has been a complete change. This very symbiotic relationship was severed by the coming of the industrial age, an age that ironically only came about because of the rivers themselves.

In what way?
Well, look at Ironbridge on the Severn. Without the river you would never have had the iron works. It created the availability of the iron in the first place, and then the need to transport it brought about the invention of the first metal boat there. Head up to the Derwent and Cromford and you’ll meet the first mechanisation powered by the water, Blake’s “dark Satanic mills”. Suddenly water meant power.

But in the modern day surely water means pleasure?
Not as much as you’d think. Of the 150,000 miles of inland river in the UK, only 41,000 miles have public access. In England and Wales we have huge restrictions on where you can travel, imposed by the vested interest of the various landowners.
I’m lucky on my local patch of river, the Stour in East Anglia. In the 70s, users of the river found out that sections were to be closed down by the reservoir companies. They took the fight to the House of Lords and won a historic victory for navigational rivers. They now have to be kept open by law, but still the vast majority of rivers are closed to navigation in a way that Edward I would have found extraordinary. He was constantly passing legislation to stop people putting in dams or weirs and stopping free navigation.

But surely we can’t allow people to navigate every section of our rivers?
Of course not. We don’t want canoes churning up the salmon beds of the Wye. But as our relationship with the river has broken down, so our understanding has too, and the majority of us don’t realise how quickly we’ve changed the river environment. It’s not that the river is no longer a resource.
We were dependant on our rivers for life, legend, politics and trade; now we see them as a resource to exploit.
In the last 50 years we’ve exploited our rivers more violently than at any other time in history and yet at the same point we’ve turned our back on them. We don’t travel by them. We hardly acknowledge them. We no longer harvest the willow that grows on their banks and indeed, our banks are now dominated by nettles which gives you an idea of the quality of the soil. The river has become an agricultural dish, awash with chemicals. In the past we let them become an industrial dish, an action we’re now repairing. Our rivers have lost their value and I think that’s rather dangerous.

But how do you get people to reconnect, to rebuild that broken relationship?
The first stage, and the most difficult, is to get across their sheer beauty. In this country we have one of the most celebrated stretches of river in the world. Pictures of it hang on the walls of museums and everyone knows it even if they don’t know its name. It’s a name I’ve already mentioned, the Stour; in particular the 6 or 7 miles that John Constable painted over 25 years. Next time you see a Constable picture, take a moment to think about what he’s capturing. It’s a working river, bustling with activity rather than just a lifeless set. Huge weather systems hang above his pictures, showing our relationship with the elements and most importantly, the river works at its own speed. Speed is what killed the British river. Until the lorry came along, people were content that it took time to transport grain to London.
This is the image of the river that I love, the image we put on tea towels. A very British river – a vital river – and one that is finely balanced. If a stretch of water is merely a place where people kayak or where water authorities ban navigation, we lose the value, both of its beauty and as a social institution.

Do you hope that your tv series will inspire people to look again at our rivers?
I hope it inspires them to take their own journey into the back garden of our country, the forgotten places that are only seen from the water. Venture on to this now deserted world and you’ll be completely isolated, flanked by bulrushes and water lilies the size of your hand. Again, I’m lucky that I live on the Stour. You can cruise along a length of waterway that is packed with fish. It feels like you’re passing through an aquarium and beneath you the bed is covered with freshwater mussel shells that reflect the sun. When Sir John Everett Millais painted Ophelia he didn’t get a hundredth of the glories of that river.
The British river is the garden of God. I’ve been in Swedish woods, I’ve been in the mountains of Montana, I’ve seen carpets of the most extraordinary wild flowers, but nothing compares to the wonder of a river in this country. Here is an extraordinary corridor of natural beauty that you can experience if you can be bothered to jump into a canoe. And what’s even more extraordinary is that you’ll be only one of a handful of people who see it.
Who do you disturb? The occasional fisherman. You’ll be no more disturbing fish anymore than a log passing by. I’ve met a lot of fisherman and decided that we should disturb as many as possible. What we all need to remember is that the river isn’t there for a few, but for the many. Rivers have been a forgotten world for far too long.

Join Griff for his River Journeys on BBC One from Sunday 26 July.

^{Picture: Modern TV}