Thames Water proposals for Oxfordshire mega-reservoir hit with Judicial Review
23rd June 2025
On 25-26 June the High Court will hear a Judicial Review case, brought by CPRE Oxfordshire and campaign group SAFERWaters, against Thames Water’s plans for a £2.6 billion mega-reservoir. We believe that the reservoir, which would be the second-largest in England and cover an area the size of Gatwick Airport, is completely un-necessary, will devastate local ecology and livelihoods, increase the risk of flooding and squander billpayers’ funds.
After a major bidder pulled out of its plans to acquire Thames Water, the crisis-hit company is at increased risk of nationalisation. Recently fined a record £123m by Ofwat, the industry regulator, the company faces further substantial penalties in the coming months. Meanwhile, customers will have to foot the bill for an eye-watering £3bn emergency loan with an interest rate of 9.75%.
Despite government data forecasting a 15% drop in water demand from 2024 to 2050, Thames Water has justified the huge project, which has a lifetime cost of £7.5 bn., according to Ofwat, using population growth estimates for the South East that exceed those for the entire country.
The question remains: why is Thames Water continuing with plans for such a huge and untested and unnecessary infrastructure project?
Derek Stork, a director of SAFERWaterS said: “This is a scandalous misuse of public money. Instead of investing in essential sewage cleanup and modern water reuse systems, Thames Water wants to build an untested bunded structure the height of an eight-story building that puts communities at risk while lining shareholder pockets.”
Water companies are incentivised to build large infrastructure because it boosts their balance sheets and shareholder value—yet Thames Water is already spending £15 million a month on consultants while shareholders have written down their investment to zero. Meanwhile, US hedge funds like Elliott Management, known for their controversial tactics, are circling.
Lisa Warne, director of CPRE Oxfordshire, said: “The UK is already one of Europe’s most wasteful water users per person – we currently reuse just 0.08% of urban wastewater, the lowest rate in Europe. The government should prioritise leakage reduction, water reuse, and efficiency, not this vanity reservoir.”
Olly Glover, MP for Didcot and Wantage said: “I, and other local Liberal Democrat colleagues, have long called for proper transparency and rigorous scrutiny of decision making around Thames Water’s plans for this enormous reservoir near Abingdon. Many of my constituents have significant concerns about the impact of such a large reservoir, and I welcome any opportunity for these concerns to be heard and addressed fully. Given their shoddy record on sewage, and wobbly finances, local residents have no faith in Thames Water to properly deliver such a huge and complex project”
The Judicial Review could lead to major revision of the government’s costly and ill-conceived water infrastructure agenda. “The Secretary of State’s decision to approve Thames Water’s plan without proper scrutiny was irrational,” added SAFERWaterS. “Customers deserve better.”