An inquiry has been launched into plans for a �3.6billion Thames super sewer that could lead to a �10 monthly rise in bills for Newham residents.

A team of internationally renowned experts led by Lord Selborne is examining the case for the 20-mile long sewer, which will be larger than the Channel Tunnel if built.

Lord Selborne said: “I welcome the opportunity to pose the questions that millions of water bill payers are starting to ask.

“The key question is whether this multi-billion pound project is the best solution to making the Thames cleaner or whether there are sensible alternatives that are cheaper, greener and less disruptive.”

Richard Aylard, Thames Water’s external affairs and sustainability director, said the tunnel was necessary as London’s Victorian sewers were no longer able to cope with current waste levels.

A Thames Water spokesperson said: “We agree that the unacceptable level of sewage discharges to the river must be resolved at minimum cost, so we welcome the appointment of this commission and look forward to providing whatever information and assistance Lord Selborne and his colleagues may require.”

The spokesperson said an independent assessment by the Thames Strategic Study had found that alternatives to the tunnel would not achieve the environmental standards required and involve greater costs and disruption.

Questions are being asked about the cost of the scheme, however, which, it is claimed, could contribute to a bill rise of 20 per cent for a quarter of customers.

As well as doubts about the cost of the project, further queries are being raised about its effectiveness and the possible threat to surrounding homes, schools and businesses.