Over 8,000 occasions of sewage water being released into waterways by Thames Water were recorded last year.

This comes after the Environment Agency published data on storm overflow spills recorded for each water company.

Storm overflows are a safety valve designed to release excess stormwater from the sewerage system into rivers or the sea during periods of rainfall and/or snowmelt to ensure they are not overwhelmed.

The Environment Agency said: "Water companies should only do this under strictly permitted conditions. EDM devices provide essential information about storm overflow use, helping to hold water companies to account."

Thames Water was found to have permitted 8,014 monitored spills in 2022, 777 of which were storm overflows.

In comparison, Southern Water permitted 16,668 monitored spills, of which 978 were storm overflows.

Overall there were 301,091 incidents of sewage going into main waterways last year for a total of 1,754,921 hours.

A Thames Water spokesperson said: “We’re pleased to see the reduction of undiluted sewage discharges from our permitted sites in 2022. Some of this will have been driven by the dry weather we saw last year, and we know what matters most is stopping the need for the discharges as quickly as possible."

Thames Water has announced its £1.6 billion investment into sewage treatment works and sewers over the next two years, with the hopes of a 50% reduction in the total annual duration of discharges across London and the Thames Valley by 2030.

“We’re the first company to provide live alerts for all untreated discharges throughout our region and this ‘near real-time’ data is available to customers as a map on our website and is also available through an open data platform for third parties, such as swimming and environmental groups, to use.

“We have a long way to go – and we certainly can’t do it on our own – but the ambition is clear.”

The data comes just weeks after Extinction Rebellion poured fake sewage down the steps of Thames Water's head office in Reading.

On March 13 protestors handed a letter to Thames Water staff condemning them for polluting the waterways.

They said: "We demand that you take responsibility for the impact of your company’s actions, that you cease the payment of all bonuses, dividends and excessive executive wages until you have stopped illegally pouring untreated sewage into our waterways."

In response, Thames Water said: "We regard all discharges of untreated sewage as unacceptable and will work with the government, Ofwat and the Environment Agency to accelerate work to stop them being necessary and are determined to be transparent.

“We are absolutely committed to protecting and enhancing our rivers and the communities who love them, and we want to make these discharges of diluted sewage unnecessary as quickly as possible."