The Thames Tideway Tunnel project, initiated by Tideway to upgrade London's outdated sewer system, involves the construction of a 25-kilometer-long tunnel to intercept spills and clean up the River Thames. The east-section contract, valued at GBP 850 million, encompasses the construction of the main tunnel and a connection tunnel, along with six shafts. Costain, VINCI Construction Grands Projets, and Bachy Soletanche (CVB) JV are responsible for executing this ambitious project, which involves coordination among 12 design disciplines and multiple supply chains.