Thames supersewer may be a waste of £1bn, says its creator

A supersewer that will add up to £65 to Londoners' annual water bills could be a waste of £1 billion, one of the project's creators claimed today.

The £3.6 billion Thames Tunnel will be built to collect 39 million tons of untreated waste that flows into the river every year.

But civil engineer Chris Binnie, ex-chairman of the Thames Tideway Strategic Study, said that instead of one big tunnel covering 20 miles of the river, two shorter tunnels could be just as effective - and about a third cheaper.

In a U-turn, Professor Binnie said: "If a way can be found not to have to build the central bit and so save a billion, it is worthwhile having a final look."

He told BBC London, in an interview tonight at 6.30, "a number of things have progressed" since his study ended in 2005. "There is more efficient use of water now," he said. "Flows into the sewers have flattened right off and, if anything, started to come down."

Work on the sewer, opposed by residents' groups and many councils, is due to start in 2013 and last seven years.

Thames Water said further studies had verified the tunnel was essential to solving the sewage problem.

The interview will air on BBC London tonight at 6.30pm