WATCH: Queen officially opens Queensferry Crossing

The Queen has officially opened the extraordinary achievement''.

She returned to the Firth of Forth to formally open the new structure 53 years after opening the neighbouring Forth Road Bridge.

As well as being a important link'' between the Lothians and Fife, in addition to the Forth road and rail bridges.

She said: The three magnificent structures we see here span three centuries, are all feats of modern engineering and a tribute to the vision and remarkable skill of those who designed and built them.''

First Minister Nicola Sturgeon told the monarch: Your Majesty, we are honoured that you are here with us today.

You, supported by the Duke of Edinburgh, have been at the centre of many key moments in Scotland's national life. We are delighted that you are also at this one.

On the day that your great-grandfather opened the original Forth Bridge in 1890, he declared it as a 'wonder of the age'.

When you opened the Forth Road Bridge in 1964, you said that it showed Scotland's determination to 'remain among the leaders in all branches of technology'.

Today, this magnificent Queensferry Crossing takes its own place as a modern marvel.''

Ms Sturgeon also addressed the crowd, saying the creation of the bridge was an outstanding achievement'' as she thanked those involved in the project.

She told them: The nation's heart is bursting with pride at what you have achieved.''

Earlier, hundreds of spectators watched as the Queen - who is to become a grandmother again after it was announced the Duchess of Cambridge is expecting her third child - formally opened the bridge by cutting a ribbon on the south side.

She was accompanied by Philip on his first official appearance alongside her since retiring from solo royal engagements last month and the royal couple met Ms Sturgeon, constructors' representatives and local officials.

The Queen - wearing a Stuart Parvin sky-blue cashmere coat with a matching hat by Angela Kelly, a printed paisley dress and a diamond thistle brooch - was welcomed on to the new crossing by an honour guard of the Royal Company of Archers and the national anthem from the Royal Regiment of Scotland band.

She was greeted by cheering crowds of children from schools from both sides of the bridge waving saltire flags and was given a floral posy by Elizabeth Martin, grand-daughter of crossing project director Michael Martin.

The Queen was then driven to the north side, where she made a short speech and unveiled a plaque.

The Red Arrows marked the occasion with a flypast while a flotilla of boats travelled under the bridge and Church of Scotland Moderator The Right Rev Dr Derek Browning blessed the structure.

The formal ceremony was the high point in a week of events marking the opening of the £1.35 billion structure - the longest three-tower, cable-stayed bridge in the world - more than a decade after plans were drawn up and after six years of construction work.

On Monday of last week, the 1.7-mile crossing was illuminated by a night-time light show to reflect the symbolic handover from contractors to the Scottish Government.

The first cars drove over the structure in the early hours of Wednesday, with many motorists sounding their horns as they travelled over it.

The bridge closed again on Friday to allow 50,000 people the once-in-a-lifetime'' chance to walk over it at the weekend. It will reopen to traffic on Thursday