A river that ran partly dry - causing a devastating impact on wildlife - is now one of the most improved in the country.

The River Darent is listed in a top 10 of improving rivers, according to the Environment Agency.

But in the late eighties it was recognised as one of the lowest flowing rivers in the country - after years of over-abstraction by water companies and industry.

By the mid nineties parts of the river, which flows from Westerham, through Dartford to join the Thames near Crayford Ness, had completely dried up in the summer.

Now, after 20 years of reducing the amount of water allowed to be taken out by 35 million litres per day, the Darent is now a haven for flow-sensitive fish and invertebrates such as brown trout and river limpet.

Audio: Ecologist Ian Humphries on the battle to clean up The Darent

It is now classed as having Good Ecological Status.

The agency has also reworked the banks in the fastest flowing sections.

The River Darent was used for trade during the 1800s and was straightened, widened and in some places given concrete banks to increase its usefulness.

A river clean-up at the river Darent at Dartford in 2004

Now walkers can follow the river at Eynsford – home to one of the earliest Norman stonework defences in the country as well as a ruined castle – through to Shoreham, Lullingstone Castle and Lullingstone Roman Villa, run by English Heritage.

It joins a list of improved rivers, including one which once ran black with coal is now an international match fishing destination, and another so polluted it was described as ‘an affront to a civilised society’, and is now a home for salmon, otters and water voles.

The transformation of these rivers has been achieved thanks to thousands of habitat improvement projects, tighter regulation of polluting industries and work with farmers, businesses and water companies to reduce pollution and improve water quality.

Ian Barker, head of land and Water at the Environment Agency, said: "Work that we have done with farmers, businesses and water companies to reduce the amount of water taken from rivers, minimise pollution and improve water quality is really paying off – as these rivers show.

"Britain’s rivers are the healthiest for over 20 years and otters, salmon and other wildlife are returning for the first time since the industrial revolution.

"But there is still more to be done, and we have plans to transform a further 9,500 miles of rivers in England and Wales by 2015 – the equivalent of the distance between the UK and Australia."