Scotland can claim JK as its own

But JK Rowling's Scottish credentials were more firmly underlined last night as a family history study suggested the creator of Harry Potter is the great-granddaughter of a pioneering doctor from Arran.

Genealogist Anthony Adolph has traced the author's family tree back to Dugald Campbell, a doctor who was born in Lamlash in 1858. Campbell went on to travel widely and achieve medical acclaim by transforming health care in Hawaii in the 19th century, setting up a hospital that treated islanders for free.

The discovery is understood to have prompted Rowling, who was born in Yate, near Bristol, to visit the Campbell family burial plot on Arran and e-mail local historians in Hawaii to find out more about her intrepid ancestor.

Mr Adolph began researching Rowling's past as a project for the genealogy magazine Family History Monthly. He told The Scotsman he initially despaired of finding the origins of Rowling's creative brilliance on the English side of her family, whose jobs ranged from labourer to engineer, blacksmith, paperhanger and storekeeper.

"They were dull as dishwater, really boring. I was thinking it was extraordinary JK seemed to have sprung out of this family who never did anything more exciting than boiling an egg," he said.

But the trail to Arran unravelled as the genealogist delved into the past of Rowling's grandmother Freda, born Louisa Caroline Watts Smith, the illegitimate offspring of an affair between the married doctor and a Clapham bookkeeper called Mary Smith. Rowling's aunt, Marian Fox, was able to supply a vital detail about her mother, who was born in 1916.

Marian, who now lives in Watford, said: "My mother remembered that until she was about eighteen, two gentlemen visited her adopted parents every year, and she was duly paraded and asked questions about her education and wellbeing.

"When she found out the truth, she was just told her father was a Doctor Campbell."

An Edinburgh University graduate, Campbell began his medical career in Hawaii. He built a hospital at Waimea and in his spare time organised cricket matches and also helped to plan Queen Victoria's Diamond Jubilee Ball in June 1897.

Married to a Canadian, Campbell fathered two sons and returned to London in 1899 where he set up a medical practice in Brixton, south London. It is during this era he is thought to have fathered Rowling's grandmother, renamed Freda by her adoptive parents.

Mr Adolph, the resident genealogist for the family tree website Genes Reunited, thought the story of Dugald Campbell provided the evidence of creative talent for which he had been searching.

The historian said: "I thought 'that's it, maybe that explains where JK Rowling gets her spark of genius from as opposed to the other very tedious relatives I came across."

Freda herself earns a place in Harry Potter history as the reported inspiration for the character of Aunt Madge. Freda's husband Stanley Volant, an engineer born in London, is name checked in Harry Potter and the Prisoner of Azkaban as one of the hero bus drivers who helps to rescue Harry.

Rowling regards Harry Potter himself as having been born in Edinburgh. The author famously wrote the early drafts of her books in Nicolson's caf in the city centre.

Mr Adolph's researches recently uncovered the Scottish roots of actor Hugh Grant. As well as having a great-great-grandfather from Perth who accompanied African explorer David Livingstone on his travels, Grant appears to be a descendant of the Jacobite Grants of Glenmoriston.