A sexual assault case against a man who claimed the victim had been touched by a ghost has collapsed due to Scotland's arcane corroboration laws.

James Mitchell, 58, the owner of Scotland’s Secret Bunker, walked free from court despite being found guilty of assaulting the young woman at the tourist attraction.

Mr Mitchell had denied the attack, and a further charge - four years later - of another assault on another young woman at the former Cold War bunker near Crail, Fife.

But the jury found the second charge not proven.

However, the case had gone ahead under 'mutual corroboration' laws. This is when a crime could be corroborated if alleged victims reported similar experiences, even in different locations.

And both offences needed to be proved beyond reasonable doubt for a conviction on either.

Sheriff Alastair Carmichael yesterday said it was “nonsensical in law” for one charge to end in conviction and the other in an acquittal.

However, he had to record a not guilty verdict on the charge Mr Mitchell had been convicted of – and the businessman walked free from Dundee Sheriff Court.

The two-day trial had heard claims that Mitchell sexually assaulted the young women, one aged 15, in separate attacks four years apart in sleeping accommodation at the underground bunker.

One of his alleged victims claimed a man fitting Mitchell’s description had entered the bedroom where she was sleeping at around 4am, put his hand under the covers and touched her leg before sneaking out.

The second girl told how she was 15 at the time and Mr Mitchell had tried to kiss her before committing a sex assault.

Police sergeant Kevin Petrie gave evidence that he questioned Mitchell over the first alleged attack in 2011.

Mitchell was asked if he had carried out the assault - which he denied, claiming he had only heard about the alleged attack from a relative.

Sgt Petrie asked him: “What were you told or what do you think happened?” Mitchell replied: “It was that long ago but somebody touched her leg.

“It was supposed to be a ghost because my daughter has seen ghosts in the place.

“We have had seances and lots of spiritual people in, spiritual people come down all the time. There was supposed to be ghosts.

“That’s what I’d heard. A ghost had touched her leg.” Why would the girls lie about this?

“What is the logical conclusion? I suggest that its that he is guilty.”

Solicitor advocate James McAteer, defending, said: “There is no corroboration between the charges and you can’t convict without both the charges. The Crown infer the bunker was a device to sexually abuse.

“There is no evidence that this is the case.”

Mitchell, of Lower Largo, denied one charge of sexual assault and three under the Sexual Offences (Scotland) Act 2009.

Under Scots Law, no criminal charge can be proved unless each crucial fact is established by evidence from more than one source.

The principle of mutual corroboration was highlighted by the case of Glasgow draper Samuel Moorov in 1930. He was convicted of a string of sexual assaults on employees over three years after it was ruled that close interrelation in time, place and circumstances between the offences amounted to a single course of conduct.

Mr Mitchell made no comment.