The Prince of Wales and the Duchess of Cornwall have visited a ruined castle famed for its appearances on screen.

The royal couple enthralled tourists at Dunnottar Castle, Stonehaven, Aberdeenshire, when they visited on Wednesday morning.

The medieval fortress is dramatically perched on a clifftop overlooking the North Sea and has featured in films including Mary Queen of Scots, Victor Frankenstein and the 1990 version of Hamlet, starring Mel Gibson.

Earlier, Charles proved to be a dab-hand at operating a digger when he officially opened the new headquarters of a nearby civil engineering firm.

On a tour of the family-run WM Donald firm at Marrlaine, he got in the cab of a Volvo excavator with automatic GPS.

Wullie Grant, 50, from Dyce, Aberdeen, showed him the controls and was impressed with the skills on show.

He said: "He's obviously done it before because he knew exactly what to do with the controls and he was very gentle.

"We were talking about the machine and how important it is for the industry. He was saying he hopes this automatic technology doesn't completely do away with people like me, and I had to agree."

Mr Grant, who is originally from Caithness in the far north of Scotland, said they also spoke about Charles' passion for that region, home to the Queen Mother's former residence the Castle of Mey.

Charles unveiled a plaque and planted a tree at the site.

Willie Donald, who founded the firm in 1977, said: "We're delighted he could come and open the office. It's a big thing for us.

"Probably one of the reasons for the visit is we did a bit of work in Ballater when it got flooded."

The company donated materials and labour to help clear up and reinstate the Deeside village, near the Balmoral estate, following devastating floods in 2015.

The royal couple, known as the Duke and Duchess of Rothesay in Scotland, also visited Stonehaven Tolbooth Museum, meeting volunteers who were given a Queen's Award for Voluntary Service earlier this year.

Charles viewed the key used by the Queen Mother to officially reopen the building in 1963, when it had been restored after falling into disrepair.

The building had originally been used as a storehouse during the construction of Dunnottar Castle, later functioning as a prison and courthouse.

Crowds greeted the couple as they then visited businesses in Stonehaven town centre, including tasting samples at the Giulianotti Ice Cream and Vintage Sweet Shop, which was founded in 1899.

They also visited Charles McHardy Butchers and Graingers Deli.