The £1.35bn Queensferry Crossing project has entered one of its most technically challenging phases.

A huge section of the bridge’s deck is being pulled out from the north shore of the Firth of Forth.

The structure, which has the technical name Approach Viaduct North (AVN), weighs more than 6000 tonnes, roughly the same as 15 fully loaded jumbo jets.

It is 226 metres long, twice the length of the pitch at Hampden Park.

The AVN was built at the site with steel that arrived in flat pack form from Shanghai in China and Darlington in England.

It is being pulled out in stages by a powerful hydraulic jack system, moving at a top speed of 12 metres an hour. The process started on February 6 and is 80% complete.

Engineers have described the feat as one of the largest and most complex operations of its type ever attempted.

The bridge is being constructed by a consortium of American, Spanish, German and Scottish companies and is due to open in December.

A workforce of 1200 has worked at the site at the peak of the five-year project.

Sub-contracts and supply orders with a total value of £246m have been awarded to Scottish firms out of a total figure of £549m for the entire project.