Ahead of the two-week connection job, a thick concrete wall separated the 25km super sewer from the 6.9km Lee Tunnel, which links Abbey Mills pumping station to Beckton sewage treatment works.
Now, those two tunnels are connected for the first time, creating the London Tideway Tunnels network and paving the way for the new system to begin its protection of the River Thames.
In the coming weeks and months, the entire system will be carefully brought online with individual combined sewage overflows being connected to the new tunnel.
This commissioning and testing phase will take place over several months, with the project expected to be fully operational in 2025.
While the Tideway team undertook the removal of the 1.5m-thick wall at Abbey Mills pumping station, a team from Thames Water was working at the eastern end at Beckton constructing a new weir wall.
