Having been lowered more than 60m below ground, the Herrenknecht mixshield machine will tunnel Tideway’s deepest section on a slight decline toward the pumping station in East London. Six TBMs have been used to create London’s ‘super sewer’, with four having already finished tunnelling.

As the last machine on the project to get underway, Selina will mine the final 5.5km stretch of Tideway from Bermondsey to Abbey Mills Pumping Station, where it is expected to hole through around 70m below ground.

The tunnel aims to intercept the roughly 39 million tonnes of raw sewage overflows estimated to enter the river every year. Running mostly under the river at depths of 30-70m, the tunnel will transfer sewage eastwards under gravity. Expected to cost around £4.1bn (US$5.47bn), the project is scheduled for completion in 2025.