THE £1.35 billion iconic construction project of its generation is now complete.

The landscape of the bridgehead area has been changed forever after the Queensferry Crossing joined the Forth Bridge and Forth Road Bridge to mark a trilogy of engineering excellence in the Firth of Forth.

Like its predecessor, the Forth Road Bridge, this structure will have a marked impact on the economy of the Cowdenbeath-Lochgelly area.

After six years of world record-breaking construction, the Queensferry Crossing opened to traffic this morning.

Spanning 1.7 miles and its towers reaching 210 metres in the air, it is the longest three-tower, cable-stayed bridge in the world and the tallest bridge in the UK.

Around 50,000 members of the public, successful through a ballot, will now walk over the bridge on Saturday and Sunday, before the Queen opens the Queensferry Crossing officially on Monday.

She will open the bridge 53 years to the day after opening the Forth Road Bridge in 1964.

She will be accompanied by the Duke of Edinburgh, who will make his first official appearance since he retired from the royal engagements in July.

Connecting Fife and Edinburgh, Nicola Sturgeon, First Minister, said the Crossing was a “feat of modern engineering” while stating her delight that more local people will get the opportunity to walk over the mega structure.

Ms Sturgeon said: “The Queensferry Crossing is a symbol of a confident, forward-looking Scotland and, as well as providing a vital transport connection for many years to come, it is a truly iconic structure and a feat of modern engineering.

“The Queensferry Experience attracted huge interest from across Scotland and beyond, demonstrating the widespread excitement and pride in the bridge. I am pleased that we are able to respond to that demand with an extra day being set aside for pedestrian access so that more people from the local area, particularly young people, can enjoy this historic occasion.”

After the Forth Road Bridge began to show signs of significant corrosion, it was no longer considered to be the long-term crossing across the Forth.

Construction work began in summer 2011, with the final bridge deck lifted into place in February this year as the project reached its final stages.

Keith Brown, Economy Secretary, said: “It’ll be a mixture of pride and relief to see traffic crossing the bridge. To think that the crossing has been completed six years from the date construction started and 10 years since development work began is a remarkable achievement for a project of this scale and complexity.

“Quite often, we see and hear of projects worldwide running significantly over budget, so I believe we should be proud of this achievement and take confidence going forward.”

While the bridge will open officially on Monday when the Queen visits, it received its first motorists on Wednesday.

Thanks to 3.5-metre wind shields running along the length of the structure, the bridge should theoretically never have to close for maintenance.

David Climie, Transport Scotland project director, said: “I’ve worked on projects across the globe and I can safely say that this has been one of the most challenging but also the most rewarding. It’s been a real rollercoaster of emotions but the over-riding emotion is one of pride. Experts from across the globe have marvelled at this achievement and so it’s nice to think there will be some recognition at home for the workforce this week too.”

Councillor David Alexander, co-leader of Fife Council, added that the links the Queensferry Crossing would provide could only benefit the Kingdom.

He said: “Improved infrastructure and better transport links between cities and regions is good for local people, communities, businesses and visitors. Access will be improved to key investment sites, industrial land and business parks across the Kingdom. I look forward to seeing Fife companies – both large and small – benefit from this infrastructure investment, both immediately when it becomes operational, and in the years to come.”

The current bridge opened up the Cowden-Gelly area to the rest of Scotland and beyond when it opened and help the spread of new industry to replace declining King Coal.

The Queensferry Crossing is certain to have the same effect bringing better connections with the rest of Scotland and beyond.