Thames Water has defended its initial round of proposals for super sewer construction sites, which included Barn Elms playing fields, despite criticism from London's Mayor.

The water company confirmed it had heard Boris Johnson's criticism of its initially preferred sites for entrances to the new sewer, but stressed "the need for the scheme has all-party support" even if the tricky bit was finding sites.

The mayor claimed this week that "Thames Water were really trying it on" with the initial plans for its super sewer construction site.

In particular, he criticised the water company's original suggestion that playing fields on the Barnes and Putney border would be a preferable option for a sewer entrance shaft.

He said: “All I can say is that I think Thames Water were really trying it on to begin with and I think some of the proposals they made were outrageous.

“I am delighted they are now scaling them back and I very much hope what they have undertaken to move the excavation from Barn Elms will be carried through and believe me, we will be following this with a lynx-like attention.”

But Thames Water insisted no concrete plans had been made and stressed it was still listening to everybody's feedback on every site and looking at potential alternative sites which may be more suitable.

A spokeswoman for the water company said: "The tricky bit is finding sites, there are no easy options.

"[But] our first phase of public consultation was the start, not the end. We have not yet made any decisions on where the sites need to be and remain open to amending our original proposals."

She added: "Our recently announced re-consideration of Carnwath Road Riverside in Fulham as an alternative to using Barn Elms demonstrates our commitment to a thorough and open consultation process."

Mr Johnson made his comments in response to questions put to him by angry residents, who live near to the Barn Elms site, at a People's Question time event held at Battersea arts centre.

Prior to proceedings, members of action group Stop The Shaft - made up of Barnes and Putney residents who live by the proposed Barn Elms site - held banners and placards outside the venue, campaigning against the possible use of the playing fields for a major sewer access point.

Issues that have concerned residents about the listing of Barn Elms as a preferred site include the fact it is greenfield land and that construction of the entrance shaft would mean 24-hour-a-day construction, work seven-days-a-week for three years.