The borough's two MPs have lodged a Commons motion challenging a Thames Water plan to pipe effluent across the borough into the River Thames.

The scheme would involve taking treated effluent from the Mogden sewage works and transporting it 15km, which will involve digging up nature reserves and parks, to a point upstream of Teddington.

There are concerns that the treated effluent will change the chemical make-up and temperature of the Thames, harming insects, plants and fish.

A key element of the scheme would see water taken from the Thames near Teddington and piped under London through to reservoirs to the east of the capital.

Thames Water is promoting the scheme on the basis it is part of a wider initiative to ensure it has enough water to keep the taps from running dry in future years river.

A key element of the scheme would see water taken from the Thames near Teddington and piped under London through to reservoirs to the east of the capital.

An Early Day Motion (EDM) has been lodged in the House of Commons by the Richmond Park MP, Sarah Olney, and the Twickenham MP, Munira Wilson, who want ministers to block the proposal.

Critics of Thames Water argue it should be doing much more to tackle mass leakages from its pipes. Currently it is losing around 630m litres a day, which is around a quarter of all the water it pays to treat and put into its pipes.

There are concerns that the treated effluent will change the chemical make-up and temperature of the Thames, harming insects, plants and fish.

The motion, which is a method of raising the profile of the issue in Parliament, requests that MPs 'acknowledges the potential impacts of Thames Water's plans for a water recycling scheme near Teddington Lock'.

It also argues that the House: "Recognises that this stretch of the Arcadian Thames is often referred to as London's countryside and is home to important animal and plant life that is rare in an urban environment; expresses concern that comprehensive environmental impact assessments have not yet been published despite the scheme being progressed; notes that the river abstraction is only required because of Thames Water's failure to maintain and invest in its pipe network and supply infrastructure;

'And further notes that the construction sites for the Teddington Direct River Abstraction will cause damage and destruction to acres of local nature reserve and parkland; further expresses concern over the impacts of the scheme on thousands of recreational and commercial river users of this part of the Thames, including boat clubs, paddleboarders and wild swimmers; and calls on the Government to advance alternative drought resilience proposals.'

Thames Water has been accused of failing to properly engage with local residents about the impact of the scheme, and even keeping them in the dark about the details of the pipeline plan from Mogden to the Thames.

This will involve digging six massive shafts along its route, including through the Ham Lands nature reserve and Moormean Park, St Margarets.

A Thames Water said: "We've worked closely with the Environment Agency throughout the consultation process and in developing the proposed river abstraction scheme at Teddington.

"We are now carefully reviewing their feedback and we're still in the very early stages of consultation and design.

"At this early stage, we have not yet confirmed the exact locations for shafts and access points associated with the proposed river abstraction scheme in Teddington. Assessments are still ongoing, and we will be sharing more information with communities and stakeholders in the autumn.

"The scheme will not negatively impact the river water quality. The treated wastewater effluent taken from Mogden Sewage Treatment Works, would go through an additional stage of treatment to ensure there is no deterioration to the water quality in the river. This would also compensate for the volume of water abstracted form the river."

Regarding leakage, the spokesperson added: "We know it's not acceptable to be losing so much precious water and would like to assure our customers finding and fixing leaks remains a top priority. In 2022/23 we fixed a total of 66,896 leaks, compared with 61,671 in 2021/22 – that's one leak every 7.5 minutes.

"We're repairing over 1,300 leaks per week – whether visible or below ground. We have over 480 people working to fix leaks with activity taking place 7 days a week and over 400 people working round the clock and mainly overnight to detect leaks not yet appearing at ground level.

"We've recently committed an additional £700million to improve water supplies. In London, we're replacing 70 miles of our leakiest water mains pipes, having met additional requirements set out by our industry regulator."