A utility company's controversial super sewer plan for the River Thames has attracted two surprising critics - officials from two American cities.

But Thames Water has rebuked comments made by council officials in Milwaukee and Chicago, who questioned whether the multi-billion pound Thames Tunnel would be a success.

Experts from the two US cities have warned that similar "deep tunnel" schemes in their areas ran over time and over budget and have failed to stop all sewage from overflowing into local rivers.

This week, Alderman Willie Hines, the president of Milwaukee Common Council, said: "If I had billions of dollars to spend, a super-sewer would not be top of my shopping list.

"I would not be looking at a deep tunnel to solve all of London's sewage problems because it certainly did not work here in Milwaukee. If I were in London's situation, I would learn from Milwaukee."

He said Thames Water should first look at prevention and improvement work to stop basement flooding and then tackle stopping rainwater from entering sewers.

Sean Wiedel, from Chicago City Council, added: "Our storms are becoming more frequent and the deep tunnel simply can't handle them."

A spokesman for Thames Water said: "Milwaukee's tunnel did what it set out to do - significantly reduce sewage discharges to the river. And a decade of independent study has shown that the Thames Tunnel is the best way to significantly tackle the 39m tonnes a year of sewage that currently overflows to London's river.

"The Thames Tunnel is not intended to tackle basement flooding. We have many additional projects, under way and in planning, to tackle sewer flooding, which is a completely separate problem."

He added introducing sustainable urban drainage systems "would cost far more than the Thames Tunnel, take longer to deliver and would not solve the problem".

Thousands of fish were killed in June this year when 450,000 tonnes of storm sewage was discharged into the River Thames.

The 20 mile long super sewer - estimated to cost £3.6bn - has courted controversy since September 2010, when Barn Elms playing fields, on the border of Putney and Barnes, was suggested as housing one of the entrances to the huge sewer system.

Residents, who could face construction work 24-hours-a-day, seven-days-a-week, for more than three years, subsequently established campaign group Stop the Shaft to lobby Thames Water over the Thames Tunnel plan, which could increase water bills for Londoners by £65 a year.

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