The Trades Union Congress and lobby group London First have endorsed a Thames Water report which says the “supersewer” scheme will create 9,000 jobs.
At its peak, the report says construction of the 15-mile sewer interceptor tunnel will directly employ 4,000 people and 5,000 more through the supply chain.
David Leam, executive director of policy at London First, said: “For London to continue to compete on the world stage it needs world-class infrastructure.
“The Thames Tunnel will not only help clean up the capital’s river, but will also contribute to the city’s economic growth and prosperity. “
Construction on the 15-mile sewer interceptor tunnel is due to start in 2016, subject to planning approval, and take seven years.
The Thames Water-led team developing the project says whoever ends up building it must use at least 20 per cent local labour.
“The new tunnel would be a shot in the arm for our economy and create thousands of decent jobs when we need them most,” said Frances O’Grady, deputy general secretary of the TUC.
“The TUC is determined to see local people benefit from skilled, unionised jobs that pay a decent wage.”
The tunnel enjoys cross-bench political support but there is significant resistance from certain communities affected by the construction, notably Hammersmith and Fulham Borough Council.
The project team is expected to report on feedback from its second phase of consultation in May.