By Jackie McGlone

SKELETONS often lie in the cobwebby dust of family closets for centuries until someone rattles them – as anyone who has ever watched the compelling TV series Who Do You Think You Are? knows after seeing one lachrymose celebrity after another unearth a shocking family secret.

Highland-born, London-based journalist Cal Flyn never understood the appeal of family history, “... the draw for all those anoraks poring over their bloodlines in the back rooms of libraries,” the 29-year-old writes in her unflinchingly honest, profoundly moving memoir, Thicker Than Water.

Then, four years ago, on a break from her London life where she had begun “to wobble” on her personal and professional perch, she returned to her parents’ Black Isle home. Jaunting around the haunts of her mother Fiona’s youth, they went to Skye – “central to my family’s history” – and visited a Portree exhibition on the diaspora.

Flyn was enchanted by an old, hand-drawn map of Gippsland, in the south-eastern corner of Australia, showing the Macalister River, “named by explorer Angus McMillan,” alongside a monochrome portrait of this tweedy chap – “sober, severe-looking with strong features...”

“He’s a relative of ours,” her mother remarked, adding that she remembered her father proudly speaking about him and that whole areas of Australia were named after him. Impressed, Flyn recalls that this revelation strangely cheered her.

Back in London, she began researching McMillan’s life, discovering that in the Australian Dictionary of Biography, the man born in 1810 in Glenbrittle, Skye, was described as “courageous, strong and generous, with a great love of his adopted country.” Flyn, who grew up in Beauly, near Inverness, read this with “a thrill of pride.” But then she discovered a news report from 2005: “A Scottish pioneer revered as one of Australia’s foremost explorers faces being erased from maps amid accusations he was responsible for the cold-blooded murder of hundreds of aborigines."

The report went on to say that the aborigines were calling for the electoral district of McMillan in the southern state of Victoria to be renamed out of respect for the men, women and children they said were slaughtered by Angus McMillan and his “Highland Brigade” in the massacre of Warrigal Creek. "The massacre was one of several attributed to McMillan and his band of Scottish settlers, who... are accused of carrying out a genocidal campaign against the aborigines for a decade.”

Unbidden, a list of search suggestions popped up on on Google: Angus McMillan Gippsland, Angus McMillan explorer, Angus McMillan massacres. Soon, Flyn had a list of chilling place names – Boney Point, Butchers Creek, Skull Creek, Slaughterhouse Gully... and the infamous 1843 Warrigal Creek massacre, "the most significant violent clash between white settlers and indigenous people in the history of Gippsland – and one of the worst recorded in Australian history.”

She had stumbled on a dark, shameful secret. On a quest to retrace her great-great-great uncle’s journey she set off for Australia, thinking that it might make an interesting travel feature, and has now made three trips over two years. She’s done countless interviews and intensive research, determined to discover all she could about McMillan the hero – the swashbuckling, hard-working, generous Scot honoured with plaques, portraits and cairns – and McMillan the villain, a bloodthirsty tyrant rampaging through the bush massacring unarmed women and children.

Of course she wanted this tough, pious, lonely man she encountered in his journals to be a hero, Flyn acknowledges when we meet in Edinburgh, where she now lives. “I think we all wish to be related to heroes, so someone like an explorer and a pioneer is such a romantic idea. The longer you invest time in getting to know someone, which I did, you come to like them. After reading McMillan’s diaries, which are held in the State Library of Victoria and which he kept during three crucial phases in his life, I felt I got to know him inside out.

“I found him, in many ways, very appealing. He was funny and crabby, and he had a very Scottish sense of humour, very sturdy, which I shared. So I was rooting for him in a way, even though I knew it was going to end in tragedy. So to begin with, he was this hero to me then he became this terrible person; I wanted it to be either black or white. If he was going to do these things, I wanted him to be a bad person. It was very uncomfortable.”

She pauses then says: “He had seemed to be rather an admirable person until I realised that he must have always had the capability to commit such brutal acts. The whole question for me is how a man, who I could relate to, had been turned into this mass murderer, but also to discover what happened to turn him back again into an apparently generous man in his later years.”

Nonetheless, she opens her book with a graphic, dramatised account of events at Warrigal Creek and spares no detail in her scrutiny of the carnage. Between 80 and 200 Gunai people were slaughtered that July day, wiping out in a single assault a substantial portion of the southern Bratawooloong clan.

The awful irony, says Flyn, who has an MA in Experimental Psychology from Lady Margaret Hall, Oxford, is that the complex man who became “the Butcher of Gippsland” had fled the horror of the Highland Clearances during which thousands of his countrymen were forced from their land to make way for sheep, only to re-enact brutal, bloody clearances of his own upon this new land.

Indeed, she tells me that Ricky Mullett, a cultural officer from the Gunaikurnai Land and Waters Aboriginal Corporation, came up with an interesting theory about this question. “He had the idea that violence was handed down to them, that they believed that this was how the world was. Actually, I think it is about power, that those who have it are terribly careless about those who don’t. The Highlanders had none, then [in Australia] they had it all. They were losers, then they were victors.”

In Australia, she fretted about becoming “a massacre tourist,” but found herself being “very generously assisted, advised and hosted” by many people, some of whom spent hours explaining Australian culture to her and discussing the modern day legacy of settlement.

Writing about massacres was not, she confides, the most difficult part of her book, in which she investigates the secret killings, asking what can be done to repair old wrongs, questioning attitudes to intergenerational guilt and Britain’s bloody colonial history, as well as looking at the racism still endemic in Australia today. She also interrogates her own history, asking who she thinks she is.

“It has been such an emotional journey, although I’ve had nothing but support and encouragement from my family, despite bringing such a dark episode of our history to light," she admits. “I found it hard writing about myself, because I always knew it would have to be a book about my feelings, with me trying to get into McMillan’s skin.”

Inevitably, she has suffered nightmarish dreams. She writes of dreaming of being pursued by faceless men with guns, of being dumb with fear and making pathetic attempts to hide beneath leaves and blankets. Another night, there would be the same scenario, “...blood spilling thick and wet across the ground, the animal groans of the wounded, the same sick thrill of fear and adrenaline. But this time they weren’t killing me. I was killing them.

“I was spending all day trying to put myself into the heads of the killers and the mind of McMillan. It was the power of imagination, I guess, and that has been really crucial to telling this story, so much of which was hidden.”

Thicker Than Water - History, Secrets and Guilt: A Memoir, by Cal Flyn

(William Collins, £16.99).