Farrans has captured the moment a tunnel boring machine completed the excavation of the 220m underground crossing of the River Tees.
The operation is part of phase 1 of a new £155m water pipeline in County Durham and Tees Valley.
Main contractor Farrans and subcontractor Joseph Gallagher have constructed two shafts on either side of the river to create a pathway beneath the river, through which new pipes will be installed.