Evidence dossier sent to police over Thames Water

The group is calling on Thames Valley Police to investigate the water company’s Chief Executive Officer (CEO) over the alleged offence.

Referring primarily to reports published by Ofwat and the Environment Agency, CAN says Thames Water’s failure to properly maintain and upgrade water and sewerage infrastructure means the statutory offence of public nuisance has arguably been committed. 

Thames Water supplies water and maintains the sewerage system for large parts of Greater London and areas surrounding the city, including Thames Valley.  

In March 2025, CAN carried out a citizen’s arrest of its CEO Christopher Weston, and sent an initial dossier of evidence to Thames Valley Police.  

The group instructed Leigh Day to prepare an updated dossier following reports published by Ofwat and the Environment Agency which were released earlier this year.  

Ofwat’s report was published in May 2025 and details significant failings by Thames Water between 2017 and 2025, resulting in record fines for the water company over what Ofwat labelled a “systemic failure” in wastewater compliance.  

The water regulator found there had been failures by Thames Water to adequately operate, maintain and upgrade its water infrastructure, as well as a failure to keep track of its performance and monitor compliance with regulations.  

In October 2025, the Environment Agency released a report assessing and comparing the performance of nine water companies in 2024. 

Thames Water was the only company given an overall rating of ‘poor performing’ by the Environment Agency, and was given a red rating (the poorest rating) in three categories including the number of serious sewerage pollution incidents.  

CAN argues that these issues amount to the statutory offence of public nuisance under section 78 of the Police, Crime, Sentencing and Courts Act 2022. 

In a letter from Leigh Day to Thames Valley Police, the group asks that the service lays out its next steps and a timeframe for an investigation into Thames Water and CEO Christopher Weston. 

A Citizen’s Arrest Network spokesperson said: 

“It’s been nearly a year since we first approached Thames Water and Chris Weston and there has been no action from the police, despite what we believe to be clear evidence of a crime. So now we are escalating. The public are sick of paying for through the nose for their water, and being met with terrible service, polluted water and poor infrastructure. We’re seeing the severe consequences of executive failure in the water industry all across the country and particularly in Kent at the moment. It’s time we stood up to them. It’s time for them to pay the price for a change.” 

Leigh Day partner Tessa Gregory, who represents CAN along with solicitor Carol Day, said: 

“Our client is arguing that problems with Thames Water’s operations are so serious that they amount to a public nuisance offence, and should be investigated by the police. A dossier of evidence detailing these issues based on extensive evaluation of the company’s performance by both Ofwat and the Environment Agency has been compiled and submitted to the police. CAN now hopes that the police will move forward with an investigation into Thames Water and CEO Christopher Weston and provide a timeframe for how they plan to proceed.”