The case was heard at Perth Sheriff Court

Robert Wallace said he was only driving so fast to get back to his post because he was suffering from an acute bout of diarrhoea.

Sheriff Lindsay Foulis took pity on Wallace, who suffers from Crohn's disease which is a serious inflammatory disease of the gastrointestinal (GI) tract.

He told Perth Sheriff Court: "In fairness, it was a mistake you made, but perhaps not one you had much control over. Having regard to the speed on this road you would normally be banned for three months or longer.

"But having regard to what you have written in mitigation and to the letter which has come from your consultant, I am going to take a very unusual course.

"I am not going to disqualify you, quite simply because of the medical information which has been provided."

Wallace, 41, from Dunfermline, Fife wrote to the court to admit speeding at 108.7 mph on the M90 between Edinburgh and Perth.

My driving licence is essential. It is part of my job. I have been driving 20 years. It was a mistake I made and not one I'll be repeating Robert Wallace

And he went on to explain the reason he was going so fast on the 70 mph limit stretch of motorway near Crook of Devon on 8 July.

Wallace said: "I know there are no excuses for excessive speed, but would like to explain the events leading up to it.

"I suffer from a medical condition known as Crohn's disease and although controlled well by medication I am prone to flare-ups which take the form of severe diarrhoea.

"On the day in question I was returning to the office at army HQ when I suffered a flare-up.

"Not knowing of any toilet in the area I was keen to make it to Dunfermline before the inevitable happened.

Two letters of support

"Although I was rushing I did not realise the speed at which I was travelling and was quite shocked when it was pointed out to me.

"I realise how foolish this was and would like to apologise for my actions."

The court was told that Wallace works as a storekeeper for the Logistics branch of the MoD based at Craigiehall in Dunfermline, Fife.

He regularly travels between 17 army recruiting offices across Scotland and asked the court to take his unblemished driving record into account.

Wallace also submitted two letters of support from commanding officers who described the incident as "out of character."

He said: "My driving licence is essential. It is part of my job. I have been driving 20 years. It was a mistake I made and not one I'll be repeating."

Sheriff Foulis said: "It's a very unusual step I'm taking in relation to this matter."