A STUDENT who walked unchallenged into the grounds of Prince Charles's Scottish estate with a crossbow while the future King was in residence has been cleared of criminal charges.

Royal Protection officers swooped on Mary McDougall after she carried the weapon for a photoshoot at Dumfries House near Cumnock, East Ayrshire, in April this year.

She was also found with a knife in a hunting jacket she was wearing and charged with breach of the peace and possessing a bladed item.

Charles, known as the Duke of Rothesay when he is in Scotland, was at the Palladian mansion for two days of engagements.

But Ms McDougall, 24, had not even realised the senior Royal was at the property or that she was doing anything wrong by entering the grounds unchallenged for the photoshoot with the decorative crossbow.

Yesterday McDougall, 24, from the nearby village of Catrine, swept as she revealed how she was arrested during evidence at her trial at Ayr Sheriff Court.

The countryside management student said she had been wearing her father's hunting jacket and did not know she had the knife, which was in a pocket.

It was agreed in court that the crossbow was for decorative purposes only and did not work.

McDougall confirmed there were no bolts or arrows and it was simply a prop for the photographs.

When asked by her solicitor Robert Logan if she was aware Charles was at the property, she replied: "I didn't know he was there. I thought there was a wedding on."

She also confirmed she had no difficulty in getting through the gates to the estate and there was no extra security on the grounds when parking near the visitor centre.

Ms McDougall added: "Nobody spoke till the police appeared. I handed the crossbow to them. I still had the jacket on.

"I didn't know what was going on. I was nervous."

She then reached into a front pocket of the jacket and realised there was a knife inside.

McDougall said: "I felt it and it was cold. I wasn't aware of the knife being in the pocket at all before that."

She said she removed the jacket and let the knife fall out of the pocket before telling police it was there.

At one point while giving evidence she broke down when her solicitor asked her if it was "quite scary" being surrounded by royal protection forces and armed response teams.

Through tears, she said: "Yes."

During his cross examination, fiscal depute Iain Gray accused McDougall of not telling police quickly enough that she was in possession of the knife.

He said: "You knew it was in your pocket, you knew you shouldn't have a knife where you were.

"That point was one chance to tell the police you've got a knife here and you didn't do that.

"It wasn't until you stood up and were taken to the police vehicle that a police witness saw an item fall from the jacket."

But McDougall responded: "I wasn't thinking. I was just thinking about my degree. The police were quite intimidating.

"They were asking us umpteen questions - 'do you know who is here today?'

"We honestly thought it was a wedding. We never seen him [Prince Charles].

"They said 'you're lucky, we could have shot you'.

"I was thinking I was going to get shot."

She said she thought the knife had been left in the jacket by her father.

In his submission, Mr Logan said: "Perhaps she did not go about it in the best way. She accepts when she discovered the knife the first thought was to remove it from her person."

Sheriff Carole Cunningham acquitted McDougall of the charge.

Prince Charles formed a charitable consortium to purchase Dumfries House in 2007. It has now been turned into a social and educational hub and the 2,000 acres grounds are open to the public all year round.