SHE was sold by her mother to a travelling showman and forced to perform gymnastics for crowds as he toured the highways and byways of 17th century Scotland.

And there the tale of the 'tumbling lassie' would have ended, had she not summoned up the courage to run away and seek refuge with a new family who swore to look after her.

And when the showman took the couple to the courts to try and have her returned, the resulting case delivered a judgement which has echoed down through the centuries with its vindication for human rights and recognition of Scottish freedoms.

The official report of the Court of Session case from 1687, listed as Reid v Scot of Harden and his Lady, simply states: “But we have no slaves in Scotland, and mothers cannot sell their bairns.”

Now the Tumbling Lassie's story has moved award-winning author Alexander McCall Smith to help the fight against modern slavery and people trafficking.

Mr McCall Smith has collaborated with composer Tom Cunningham to produce a special operetta which will be given its world premiere at the Tumbling Lassie Charity Ball in Edinburgh.

The Herald:

“The story of the Tumbling Lassie is a very moving one,” said Mr McCall Smith.

“The first time I heard it, I knew that I wanted to write about it and now I have had the opportunity to write the libretto of an operetta on the theme. It is impossible not to be profoundly moved by this extraordinary tale.

“Slavery might have been rejected by Scottish judges in the late 17th century, but unfortunately the modern evils of trafficking still persist. The story of the Tumbling Lassie still has resonance today.”

The ball is the brainchild of Alan McLean, QC, who found reference to the little-known case in a footnote in a law book and was struck by the rejection of slavery as an early vindication of human rights.

He and colleagues in the Faculty of Advocates formed the Tumbling Lassie Committee, and have staged two fund-raising balls and seminars, raising more than £30,000 for two charities, Trafficking Awareness Raising Alliance (TARA) and International Justice Mission (IJM),

Alan McLean said: “The Tumbling Lassie Committee simply asked Alexander McCall Smith if he would be prepared to donate a couple of his books for an auction at our previous Ball, but with extraordinary generosity he offered to do much, much more than that.

"We are thrilled that he and Tom Cunningham have written this operetta especially for us and that it will have its premiere at the Tumbling Lassie Ball next spring. We can’t thank them enough.

“We have set the bar high with our previous two events, but we are sure that with Alexander and Tom’s contribution we can top that success in 2018.

"We know that every penny we manage to raise helps tackle the evils of slavery and human trafficking at home and abroad and we hope that many people will be inspired to support this unique event.”

In a previous collaboration, Mr McCall Smith and Tom Cunningham wrote The Okavango Macbeth, a chamber opera set in Botswana’s Okavango Delta.

It tells a story of the struggle for power among competing baboons in their matriarchal society, thus drawing parallels with Macbeth.

The author is one of Scotland's most successful writers, whose series of novels featuring the No1 Ladies Detective Agency, the philosopher Isabel Dalhousie and the residents of 44 Scotland street, Edinburgh, have sold in the millions.