Thames Water has hit back at claims it has trebled sewage dumping in the River Kennet - at the same time a pledging its support to clean it up.

Environment group Action for the River Kennet lodged an environment information request which showed the increase in the number of hours sewage was being discharged,

Thames Water refuted that this meant an increase in actual volumes of sewage, as it only monitors durations of spills and not volumes.

“Our view is that discharges of untreated sewage are simply unacceptable, even when they are legally permitted, and we will work with government, Ofwat and the Environment Agency to accelerate work to stop them being necessary," said a Thames Water spokesperson.

“We believe rivers should be beautiful, natural places that provide opportunities for recreation, relaxation and inspiration for our communities. Eliminating sewage discharges is not going to be quick, or easy, or inexpensive and we will need the continued support of our customers and regulators, as well as extensive collaboration with local communities and other stakeholders, to achieve it.  We have a long way to go – and we certainly can’t do it on our own – but the ambition is clear.

“Our aim will always be to try and do the right thing for our rivers and for the communities who love and value them. We’re passionate that we set out a stretching ambition and learn from past mistakes. We’re honoured to be one of the custodians of these incredible environments and are committed that we work tirelessly to protect and enhance them.”

ARK said the response to its enquiry showed that in 2020 Marlborough sewage treatment works tipped untreated sewage into the River Kennet for 2,872 hours, the equivalent of 119 days and nights of continuous dumping. They claim this compares with a total of 989 hours in 2019.

Action for the River Kennet’s Director Charlotte Hitchmough said:"We want to see the Environment Agency take strong action to clamp down on sewage pollution, we want Thames Water to make more investment to prevent pollution, and we want the planning system to recognise that the current sewer network is inadequate, and to stop allowing more homes to be added to sewer networks that already can’t cope."

ARK also claims Marlborough is not an isolated case, saying data from sewage treatment works across the catchment paint a similar picture of persistent pollution.