There has been much discussion about the potential ownership structures of the water sector in England and Wales over recent months, but there has been very little thought given to actual operation of the industry.

And nowhere is this clearer than when it comes to the environment. It simply isn’t good enough to assert that a change of ownership would automatically lead to a cleaning-up of the natural water environment, an acute issue given the challenges of climate change, particularly when we look back at what has driven the considerable progress on overcoming environmental challenges over the past 30 years.

Throughout much of the 20th century our rivers and beaches were in a state of crisis. The Thames was declared dead in the 1950s. In 1988, more than a third of our beaches fell below legal standards. But today, less than half a per cent don’t make the grade, thanks in large part to almost £30bn of investment in the environment since privatisation.

But this change hasn’t come in a vacuum. EU regulations have played a crucial role in raising standards and driving changes to the structures of the water sector. The realisation that the vast costs associated with meeting these standards could not be met by government funds strengthened significantly the case for private investment; in that sense, privatisation in the late 1980s was a pragmatic response to an environmental imperative.

Even now, however, the need for investment is as pressing as ever. There is a lot more to do as far as our waterways are concerned. That is why we must not only maintain the standards we have achieved, but also ensure the water industry does not fall prey to ideological siren calls for nationalisation when the focus should be on how best to improve on present standards.

As a report from Green Alliance, From Blue to Green: how to get the best from the environment from spending on water, clearly explains, instead of going backwards we need to build on the progress over the past 30 years to encourage and support every farmer to manage their land in a way that respects the water environment. We need to continue and extend that work, helping farmers to provide effective stewardship of their land. In so doing, we will further reduce pollution of our watercourses and, of course, reduce pressure on water bills.

The agriculture bill is being debated by MPs today, and we must take this opportunity to ensure that common agricultural policy subsidies are reformed so that good farming practices are rewarded where they increase environmental standards.

We must also ensure that we do not go back to a system of ownership in which the water sector will always lose out when in competition for scarce government funds with schools and hospitals.

That is why, as a passionate environmentalist and champion of real investment in our public services, I do not want to go back to the 1980s when the UK was called the “dirty man of Europe”, with beaches overflowing with sewage, filthy rivers, excessive power station emissions and a poor conservation framework.

When it comes to ensuring we have clean water and a safe marine environment we cannot allow ideology to be the master of fact. That means resisting those who wish to reduce standards just as forcefully as we should resist simplistic calls for state ownership.

To further improve our rivers and beaches we need real investment supported by smart and efficient regulation, not dogma. It is about time we focused our minds on the issues at hand, and that means reaching for pragmatic and workable solutions to the challenges facing the natural environment.

• Angela Smith is the Labour MP for Penistone and Stocksbridge and chair of the all-party parliamentary group on water. Disclosure: the all-party parliamentary group’s secretariat services are provided by Connect and paid for by water industry interests.

• This article was corrected on 10 October to 2018. An earlier version referred to Britain, when it should have referred to England and Wales. Water is nationalised in Scotland and Northern Ireland. The disclosure in the author note was added on 11 October.