‘Super sewer’ owner Thames Tideway Tunnel on Friday said cost pressures had put a strain on finances for the project’s £4.2 billion budget.
“Following significant progress on the project and now having mobilised on 20 of our 21 sites, Tideway has identified several cost pressures in the programme,” holding company Bazalgette said.
The construction venture, which is building the 25km tunnel under the Thames, said a contingency allowance set aside for possible cost over-runs had been “substantially eroded” due to the strain.
But the firm said it was still on time and budget after stepping up cost-savings measures, such as avoiding duplicate work from contractors.
“There have been a number of complex engineering challenges and risks to overcome in the early stages of the project. With these behind us and having put in place several measures to reduce cost our budget is intact," a spokesperson said.
"Tunnelling for the project started this week from our site in Battersea and we are set to complete the project on schedule and to budget."
Troublesome engineering challenges, including at Blackfriars and Albert Embankment, are part of the problem.
Tideway, which is backed by a host of City infrastructure backers including Allianz and Dalmore Capital, is providing £3.1 billion of the budget with Thames Water supplying the rest.
