Hammersmith and Fulham Council has accused Thames Water of ripping off its customers.
They claim that the super sewer isn't necessary - and that the company is being motivated by financial gain, rather than the environment.
“Water industry experts are lining up to say that Thames Water’s case for the super sewer is flawed. The Thames has won awards for its cleanliness but we all agree that it could be cleaner still. The question is how this is delivered and it appears Thames Water’s true motivation for pushing through this massive concrete tunnel has more to do with financial gain than cleanliness.”
The council argues that there are alternative solutions to the capital's sewage overflow problems - new drainage systems, for example, that could minimise the amount of fresh rain water entering the sewerage system.
They also claim that Thames Water stands to make "colossal returns at bill payers' expense".
More top news
Every Christmas gets a bit more desperate for one dog at Battersea. Can you help?
The problem has meant that no trains are able to run through Gatwick Airport rail station in West Sussex.
Schoolchildren found Eragon wearing a Christmas jumper in the bag filled with dog food, treats and a tear-jerking note, in a church.