A public survey on the controversial “super sewer” has been branded “inept in the extreme”.

Richmond Council issued the damning verdict on Thames Water’s consultation after it earmarked playing fields at Barn Elms as the preferred site for the entrance to the 20-mile tunnel.

Councillor Virginia Morris, Richmond Council’s cabinet member for environment, spoke out in support of Barnes residents angered by the plans, which centre on the southern edge of the picturesque green space.

She said: “We recognise the potential benefits of the Thames Tunnel project - no one wants to see rivers of sewage flowing through the capital.

“However, Thames Water has thus far totally failed to make the case for the Barn Elms site or the disruption it would cause.

“Thames Water’s consultation has been inept in the extreme, they need to engage fully with the community to gain support if they are going to begin to make the case for Barn Elms.”

If work goes ahead residents face seven years of building work, including three-and-a-half-years’ disruption, 24 hours a day, while the tunnel entrance is formed.

An action group, named Stop the Shaft, has been set up by residents to highlight concerns about the impact proposals could have on the surrounding communities.

Sian Baxter, a Stop the Shaft co-ordinator, said neighbouring homeowners felt they had not been adequately warned of plans.

Ms Baxter, of Lower Richmond Road, said: "We know, officially, Thames Water failed to notify residents in the area - they said there was a problem with the post.

"We have ourselves had to send round leaflets to tell people.

“We have covered 5,000 households in the area and are pushing for an extension of the consultation process.

"It is absolutely horrific. Barnes and Putney are renowned for their green area and to have it [potentially] devastated and not told about it is so profoundly upsetting."

Thames Water, which is currently asking for public opinion on the plan, also faces opposition from neighbouring Wandsworth Council which believes the proposals would be severely disruptive to people on both the Barnes and Putney side of the Barn Elms site.

Richard Aylard, Thames Water's external affairs and sustainability director, said: "We have tried hard to notify local people about how they can get involved in the consultation process because we genuinely want their involvement.

"Where people feel there have been gaps, we are happy to stage extra events, so that everyone has the opportunity to have their say, prior to the closing date for phase one consultation on December 20.

"It's important for us to get detailed feedback from as many people as possible, so we can use if to refine, and where possible amend, our initial proposals to reflect the concerns and suggestions of local communities."