The Thames Tideway Tunnel was granted planning consent by Environment Secretary and Liz Truss and Communities Secretary Eric Pickles despite the opposition of many residents affected by its construction.
When completed the tunnel will run from the Acton Storm Tanks in West London to the Abbey Mills pumping station in East London
Work to built the tunnel is expected to start in 2016 and will be completed by 2023.
Thames Water will pass the £4.2bn cost on to householders who could see bills rise by as much as £80 per year.
Announcing the Government’s decision, Mr Pickles said: “This is a challenging infrastructure project, but it is clear that the Thames Tunnel will help modernise London’s ageing Victorian sewerage system, and make the River Thames cleaner and safer.”
Thames say the scheme is essential to stop sewage overspilling into the Thames during periods of high rainfall and claim last year it could have stopped 97% of such sewage spills.
Andy Mitchell, chief executive of Thames Tideway Tunnel, said: “Hardly a week goes by when untreated sewage is pouring in to London’s river and we are pleased that we can now start to tackle this archaic problem.
“This is a huge project but it’s a huge problem, and we can now get on with tackling it. It’s no easy task, but we’re confident that we can deliver this project and still achieve our aim of minimising the impact on our customer bills.”
