Campaigners working to improve the quality of the River Kennet in Marlborough are opposing plans by Thames Water to hugely increase the amount it pumps out of the river to provide tap water to homes in Swindon.

Members of Action for the River Kennet say wildlife will suffer if the Environment Agency approves the company’s application to take an extra 639 million litres of water from its pumping station at Axford each year for the next two years.

But a spokesman for Thames Water denied it wanted to take extra water out of the river. He said: "We have applied for a renewal of our existing abstraction licence at Axford - not to increase it. "We fully support Environment Agency plans to reduce over the long term the amount of water we abstract at Axford in order to ease pressure on the unique chalk stream habitats of the Kennet. "But until funding arrangements are confirmed by the Agency for building a £10m transfer pipe to supply water to south Swindon from the River Thames instead of the Kennet then we must continue to rely on the Kennet."

ARK chairman Geoffrey Findlay said: “This is a disappointing step. In 2008 Thames Water agreed to take less water from the borehole at Axford and to provide an alternative, sustainable water supply to south Swindon.

“If this licence is granted, the Kennet and its wildlife will pay the price.” ARK has been campaigning since 1991 to reduce the level of water abstraction from the River Kennet and its underground aquifers.

Charlotte Hitchmough, director of ARK, said the river was recognised by the World Wildlife Fund as one of the world’s finest chalk streams and evidence accepted by DEFRA and the Environment Agency shows that taking water out of the aquifer caused serious environmental damage.

Mrs Hitchmough said: “Every drop of water taken out of the borehole leaves less for the wildlife that lives in the river and along the river banks. We are draining our river dry because it’s a cheap source of water.”

She said ARK would continue to push Thames Water to find a sustainable alternative water source.

Anyone wishing to object to the application should email PSC-WaterResources@environment-agency.gov.uk before March 24.