The £200m waste water treatment scheme will be progressed as part of United Utilities’ existing AMP5 process alliance framework.

Work involves extending the current treatment works in Vauxhall into the adjacent dock along with major upgrades to plant.

The existing outfall will also be extended into the River Mersey, dispersing treated waste water even further into the estuary to meet new EU standards.

Greg Fitzgerald, Chief Executive of Galliford Try, said: “We are delighted to secure this business from an existing framework client. It builds on our track record in delivering both clean and waste water infrastructure projects.”

The deal is another coup for Costain in the water sector after Severn Trent recently extended its AMP5 contract by around £45m.