The Tory leadership frontrunner, Liz Truss, was responsible for cutting millions of pounds of funding earmarked for tackling water pollution during her time as environment secretary, the Guardian can reveal. Truss, who was in charge at the Department for Environment, Food and Rural Affairs (Defra) between 2014 and 2016, oversaw “efficiency” plans set out in the 2015 spending review to reduce Environment Agency funding by £235m. This included a £24m cut from a government grant for environmental protection, including surveillance of water companies to prevent the dumping of raw sewage, between 2014-15 and 2016-17, according to the National Audit Office. It represents almost a quarter of the funding cut from this area between 2010, when the grant stood at £120m, and 2020, by which time it had fallen to £40m. Labour analysis of official figures shows that since 2016 raw sewage discharge in England and Wales has doubled, from 14.7 spill events per overflow to 29.4 in 2021. Greenpeace said the figures showed Truss had “sewage on her hands”. The Environment Agency has called for the government to reverse the cuts but campaigners want the next prime minister to go further and also give the body the power to properly monitor water companies over sewage, rather than allowing them to self-report discharges. It follows the finding that 24% of sewage overflow pipes at popular seaside resorts in England and Wales have monitors that are faulty or do not have monitors at all, meaning people could be swimming in human waste this summer without realising. Last year the head of the Environment Agency, James Bevan, called on the government to reinstate the funds, saying that given the length of the country’s river systems, having “only a few hundred people to oversee them is a pretty tall ask”. He told MPs: “It has had an effect on our capacity to monitor, to enforce the rules and to help improve the environment where we think it needs doing. Honestly, I would like to see that grant restored. I would like to get back to where we were 10 years ago, and I think it would make a massive difference.” In response to the findings, the shadow environment secretary, Jim McMahon, said: “The country is facing a crisis in our water supply. Our water infrastructure is at bursting point with billions of litres of water being wasted every day and raw sewage being dumped into our waters. “The fact that Liz Truss was the one to cut the EA so severely not only demonstrates her lack of foresight but also her lack of care for the detail, in recognising the need to adapt to the serious flooding that had just happened on her watch.” Environment Agency insiders said that after Truss’s cuts, staff were moved away from environmental monitoring towards flood protection, and the number of samples taken from rivers went down dramatically. Vaughan Lewis, a senior consultant for the agency, told the Guardian: “They plummeted to the point it was impossible for the Environment Agency to know what’s going on. They had no control or monitoring capability that was meaningful. They ceded the control of monitoring to water companies, which ended up being able to mark their own homework. They take their own samples and assess whether they are being compliant. “We saw that doesn’t work – look what happened with Southern Water, which didn’t declare its pollution incidents and ended up being fined by the EA when they were found out. There are suspicions this could be happening across the board. It has been left to citizen scientists who monitor and fill in the gaps.” Lewis added: “Lots of this would have happened under Liz Truss; she was there when some of those cuts were made. She was a poor minister and the Environment Agency has been cut to the bone and it can’t monitor or regulate effectively.” As environment secretary, Truss defended the cuts by saying “there are ways we can make savings as a department”, citing better use of technology and inter-agency working. She is already facing questions about why she was registered absent from a vote on a Labour amendment in the House of Commons that aimed to place legal obligations on water companies to stop polluting England’s waterways during heavy rainfall. A spokesperson for Truss said: “These spending reductions were part of a wider drive from central government to find efficiencies across department budgets and government agencies. “It’s vital we get a grip on pollution in our water and ensure it is clean and safe for all to enjoy. As prime minister, Liz will make sure the necessary action is taken to deliver this.” Greenpeace UK’s chief scientist, Dr Doug Parr, said: “A decade of budget cuts and government deregulation has left the Environment Agency, almost literally, up shit creek without a paddle. The growing tsunami of sewage unleashed on to Britain’s waterways is a shocking demonstration of how undermining our regulators leads to a disregard for nature and those meant to protect it. “That our likely future prime minister was an instigator of cuts to the money used to protect our rivers, and so helped cause this environmental catastrophe, doesn’t bode well for the UK’s protection of the natural world. Liz Truss has sewage on her hands.” Hugo Tagholm, the chief executive of Surfers Against Sewage, said: “Self-monitoring has clearly failed for the water industry, the culture of self-reporting has clearly failed, millions of hours of sewage pollution going into our waterways every year, it’s a failed model.” Martin Salter, from the Angling Trust, said: “The consequences of these ill-advised cuts to the Environment Agency’s pollution monitoring capabilities are now present for all to see and smell, with raw sewage flowing down our rivers and dead fish and other wildlife washed up on the banks with depressing regularity. “The move away from tougher regulation in favour of allowing water companies to report on their own failures has created a polluter’s charter, as evidenced by the recent prosecution of Southern Water for deliberately falsifying their discharge data.” The Environment Agency has long bemoaned its lack of funding and power, underpinned by a lack of ambition from ministers on tackling waste. In 2020 it said it recognised that a “huge gap is opening up between the outcomes we want to achieve and our ability to achieve them”, and estimated that “at the current rate of progress” it would take more than 200 years to reach the government’s target of at least 75% of waters being close to their natural state. • This article was amended on 1 September 2022. Labour’s analysis of the raw sewage discharge data for 2021 showed 29.4 spill events per overflow, not 29.3 as an earlier version said.