Jesse Norman writes for The Times.

At a time when political debate is dominated by public concern over pollution and other threats to the environment, few things are more important than the protection of our rivers and the ecosystems, livelihoods and businesses they support.

That is the argument I will be making today, in a debate on water quality in the House of Commons.

The River Wye, which flows from the middle of Wales through my constituency and on towards the Severn, is a case in point.

The Wye is one of the glories of our country, a priceless national asset celebrated for its beauty since the 18th century, when it inspired the first domestic tourism and the aesthetic movement known as the picturesque.

Yet the Wye is at grievous risk from phosphate pollution, which destroys river life and natural habitats. It is the victim of what a recent Commons report identified as a “chemical cocktail” of sewage, slurry and plastic in our rivers, only 14 per cent of which meet good ecological standards.

The problem is complex, but the path to a solution is well understood and likely to be relatively inexpensive. But bureaucratic delays and inertia have impeded the way forward.

Much recent public attention has focused on the effect of sewage discharges, but the much bigger issue is the leaching of phosphate and other chemicals that have built up in the soil over many years of intensive agriculture on both sides of the border.

This has been exacerbated by the rapid development of chicken sheds in England and Wales. Chicken litter is a particularly potent source of phosphate, and discharges upstream are naturally carried all the way down the river.

Three agencies are crucial to the clean-up: the Environment Agency, Natural England and Natural Resources Wales. All are needed, together with Ofwat, which regulates the water companies, and with guiding support from the Welsh and UK governments.

The solution is evident, as I have argued for more than two years. It is for these organisations to develop a single team and a joint long-term cross-agency strategy covering the river from source to mouth. It will require testing, monitoring and enforcement. But once the team and strategy are in place, we will have the framework needed to secure the necessary funding.

And it is nothing new. A very similar issue was addressed in relation to the River Tweed, which straddles the border between England and Scotland, as long ago as 1807, and the Tweed is still regulated by its own commissioners. So the precedent is there.

It was that pioneering environmentalist Margaret Thatcher who said in 1988, “It’s we Conservatives who are not merely friends of the Earth — we are its guardians and trustees for generations to come.

“The core of Tory philosophy and the case for protecting the environment are the same. No generation has a freehold on this Earth. All we have is a life tenancy — with a full repairing lease. This government intends to meet the terms of that lease in full.”

She was right, and that obligation remains today. Now the agencies, the regulator and the Welsh and UK governments need to step up to the mark.

Jesse Norman is a former Treasury minister and MP for Hereford