£5bn Thames Tideway Tunnel completed


The £5 billion Thames Tideway Tunnel in London has been completed after an eight-year construction process.  

Credit: Tideway.

A 1,200-tonne concrete ‘cap’ (pictured above) was recently placed over the 70-metre shaft at Abbey Mills Pumping Station in Stratford, East London, using a purpose-built gantry crane, marking the end of the underground civil engineering and major construction works on the 15-mile-long ‘super-sewer’ infrastructure. 

“This is the moment we’ve all been waiting for,” said Tideway CEO Andy Mitchell. “The underground civil engineering on the Tideway project is now complete following eight years of dedicated hard work from all our teams working in the capital.”   

He added: “There is still work to do – we need to finish some above-ground structures and, crucially, test the system – but this nonetheless marks an absolutely critical milestone for the Tideway project and for London.” 

Robert Ricketts, project manager at Abbey Mills Pumping Station, said: “This [five-hour] manoeuvre was a complex operation and required careful collaboration between various teams working on this project.” 

Next, Tideway will begin commissioning the sewage system, ensuring it functions as designed, over the summer. 

Live storm sewage flows will be diverted into the new infrastructure, protecting River Thames for the first time. 

Started in 2016, construction had been aimed for completion by this year, but was rescheduled owing to delays brought about by the pandemic.    

Credit: Tideway.

The tunnel is due to be fully operational under Thames Water in the second half of 2025, at which point it could capture up to 95 per cent of overflows from London’s sewerage network, improving the water quality of the Thames and the environment.  


  • VINCI Construction Grands Projets, Bachy Soletanche, Costain (JV)    
  • Ferrovial, Laing O’Rourke (JV)    
  • Balfour Beatty, Morgan Sindall, Bam Nuttall (JV) 

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