The convoy of marine equipment, which includes a 125m tower crane barge, arrived in the Mersey estuary after travelling up the River Mersey from Liverpool Docks.

The barges are being used to build temporary cofferdams to enable construction to begin of the pylons that will support the three towers of the 1,000m-long cable-stayed bridge.

The work involves driving steel sheet piles into the riverbed to form two circular enclosed spaces: an outer circle with a diameter of 40m and a 20m-diameter inner circle. Approximately 300 steel piles will be used for each cofferdam: about 200 for the outer circle and 100 for the inner circle.

It is expected to take about 30 days to build each of the three cofferdams. They will be visible in the river for the duration of the three-and-a-half-year construction project and removed once the work is complete.