All of England’s rivers and lakes polluted with chemicals, officials say

The Environment Agency stressed that this year’s data could not be directly compared with 2019 because it had changed its methods.

In particular, it said the steep fall in the number of lakes ranked as good – down about half from 2019 – largely reflected a change in how its experts now assess them, rather than a genuine decline in their condition.

Its chair, Alan Lovell, has acknowledged that too many water bodies were “still not achieving the standards we want to see”, adding that the agency was “transforming our enforcement work” with its largest ever workforce.

But Prof Johnes said the true picture was almost certainly worse than the classifications suggested.

The scheme was “not fit for purpose”, she said, measuring too few pollutants too infrequently, and missing nitrogen and other substances scientists have long understood to be driving rivers’ decline.

The findings come as much of England sits in official drought, with rivers running low and more than 20 million people facing hosepipe bans.

Lower flows can concentrate the very pollution the new data is designed to track, leaving fish and other aquatic life exposed to more dangerous levels.

Climate change is expected to bring drier and hotter summers which could further exacerbate this issue.

Asked directly whether England’s waters were healthier than six or seven years ago, Prof Johnes said: “No, definitely not.”