London super sewer to cost less than expected, says Ofwat

Regulator awards licence to Bazalgette Tunnel to start building along Thames and says bidding process has cut costs

London's new 4.2bn super sewer will cost customers less than expected, the water regulator has said, as it awarded a licence to start building the tunnel next year.

Ofwat said Bazalgette Tunnel Ltd, a company formed to lead the project, would build the Thames tideway tunnel. The 16-mile (25km) sewer is designed to reduce the 39m tonnes of untreated sewage that flows into the river Thames each year.