Thames Water has said it needs to discharge sewage into rivers to stop people wading through it in their homes.

Water firms have come under fire for high rates of water leaking from the network, profits and executive pay, and for sewage pouring into rivers and the sea in the recent heavy rainfall.

“The overflows prevent the sewage backing up through the pipes and flooding properties," a spokesman said previously.

“Essentially stopping the sewage spilling out of toilets and plugholes and also coming up through manholes in gardens, streets and other open spaces.

“Think of them as a pressure relief valve or the overflow in your sink or bathtub.”

Last year MPs voted on an amendment to the Environment Bill that would have called for companies like Thames Water to do all it could to prevent the need for storm overflow discharges and to demonstrate improvements to the sewage networks.

But it was voted that these conditions be removed from the wording of the bill.

Thames Water has previously said that discharges of untreated sewage are 'unacceptable' and indicated it was working with the Government and the Environment Agency to take steps to stop them.

“It isn’t a case of alternatives as such but a combination of several things that need to happen to reduce discharges," said Thames Water.

“This includes increasing capacity at sewage treatment sites where needed, stopping rainwater/surface water entering the sewers and therefore overwhelming them, stopping groundwater getting into the sewers and overwhelming them and reducing blockages which can reduce capacity in the network."