Furious residents plagued by the stench from an Isleworth sewage works have branded plans to boost capacity by more than a third 'unacceptable'.
Thames Water wants to increase the amount of effluent treated at Mogden Sewage Works from 690 to 1,074 megalitres a day, angering nearby household who insist the company should deal with existing problems before expanding.
More than 10,000 people are estimated to suffer from the pong or mosquitoes breeding at Mogden, many of whom are fighting an ongoing legal battle with the owners.
They won a partial victory in 2005, when Thames Water signed a legally-binding agreement to complete major improvements within 42 months.
But, despite that deadline looming next month, complaints for June 2008 were actually up on the same period last year.
Thames Water applied last month to build 15 extra settlement tanks in the west of the site and hopes to begin the four-year project this winter if its bid proves successful.
It claims increasing the flow of waste will help stop smelly water standing stagnant and prevent raw sewage flowing into the Thames during heavy rainfall.
But Steve Taylor, of Mogden Residents Action Group (MRAG), said it was 'unacceptable' for Thames Water to begin the expansion work before February, when it is due to face accusations of negligence in court.
"Thames Water says that if massive expansion of Mogden goes ahead there will be no increase in odour, but it has no evidence whatsoever to support its claim," he added.
"If its planning application is permitted it will be a travesty for residents in the boroughs of Hounslow and Richmond."
A spokeswoman for Thames Water said the work would protect the Thames' diverse wildlife by slashing discharges into the river by 80 per cent.
She added that the primary sewage treatment area would also be covered as part of the improvements, the success of which will be assessed by independent odour experts.
To have your say on the planning application, which is available to view at Isleworth Library, email email@example.com or call 020 8583 4968.