The real-life Scots who put Logan Roy's fictional family in Succession in the shade – Richard McLauchlan

It seems as if everyone is obsessed with Sky TV’s Succession. Billboards are announcing the fourth and final season, newspapers are teeming with columns and reviews about it, and the Twitter-sphere is abuzz with viewers’ comments.

Brian Cox’s Logan Roy is New York-based but Dundee born. He could rival Malcolm Tucker for television’s most foul-mouthed, bad-tempered Scot. That’s all part of the show’s appeal, as is Roy’s lavish lifestyle and tortuous relationships with his love-starved, power-hungry children.

But fact can be more amazing than fiction. That’s why I’ve written a book about a real Scottish family whose achievements and personalities make the Roys look rather pedestrian. And yet the Haldanes of Cloan (their Perthshire home) are largely unknown to the public.

Most people have heard about the great English intellectual dynasties, the Darwins and the Huxleys. But families don’t get much brainier than the Haldanes, and no single family in the UK has made a greater impact on contemporary society.

If Logan is the dominant Roy, then Richard Burdon Haldane is the all-pervading presence for the Haldanes, the one still referred to as ‘Uncle Richard’ by today’s family members, though he died almost a century ago. Where would Britain be without him?

Serving as Secretary of State for War between 1905 and 1912, his political and military contemporaries believed the First World War was won because of his groundbreaking army reforms. The British Expeditionary Force, the Territorial Army, the Officers’ Training Corps, the RAF, MI5 and MI6 – all owe their existence to Richard.

That’s not half of his achievements. He created Imperial College London; he made it possible for Oscar Wilde to write De Profundis from his prison cell; he hosted Albert Einstein on his first visit to the UK in 1921; and he was offered the chair of moral philosophy at St Andrews. Having given long service to the Liberals, he became the first-ever Labour Lord Chancellor in 1924. Oh and by the way, Richard radically reshaped the Canadian constitution.

Through his siblings, the Haldane impact went further still. Richard’s brother, Professor John Scott Haldane, invented the first effective gas masks of the First World War and designed the first prototype spacesuit. His calculations stopped divers getting ‘the Bends’ when re-emerging from high pressures of water and, because of his genius, canaries ended up in coal mines to provide early-warning signals of dangerous gasses. Taken together, John’s work saved many thousands of lives.

The first generation of the extraordinary Haldanes in the 1880, from left: Richard, their mother Mary, Elizabeth and John (Picture: Justin Piperger/RW Haldane's private collection)

The sister of these two brainiacs, Elizabeth, was said to be brighter than the pair of them. While not busy translating Descartes and Hegel, she managed Edinburgh Royal Infirmary, sat on Royal Commissions, and became the first female Justice of the Peace in Scotland. The Scotsman obituary of 1937 called Elizabeth, “one of the most representative figures of her time”.

The Haldanes weren’t all brain, they had character too. As you’d hope for a good Edwardian patriarch, Richard is said to have had “the finest cellar and the best table in Scotland”, and his girth reflected it wonderfully. When Winston Churchill one day ran into Richard in the Commons’ lobby, he began patting the noble belly of his ministerial colleague. Smirking, Churchill asked, “What’s in there, Haldane?” The response was exquisite. “If it’s a boy I shall call him John. If it’s a girl I shall call her Mary. But if it’s only wind, I shall call it Winston.”

The next generation of Haldanes took character to new levels. With a father like John, JBS Haldane was always going to be special. When he was seven, he asked his dad for help as he attempted to classify his seashell collection. John casually turned to his bookcase and pulled down a two-volume textbook of zoology and handed it to the little boy, who eyed it in amazement. It was written in German.

JBS’s subsequent career defies categories. Whizzing through Eton and Oxford at the top of every class, he never had a scientific degree to his name but became the foremost geneticist and evolutionary biologist of his generation. During the Great War, Field Marshal Haig called him “the bravest and dirtiest officer in my Army”. A fervent Marxist, he fought again in the Spanish Civil War where his cavalier attitude to danger almost got Ernest Hemingway killed. During the Cold War, MI5 – his uncle’s creation – was convinced JBS was a spy.

The Haldane family patriarch, Richard Burdon Haldane, as Lord Chancellor in 1912 (Picture: Justin Piperger/RW Haldane's private collection)

The Haldanes were visionaries. In 1919, Richard correctly predicted the exact year a Second World War would break out. In 1924, JBS foresaw a Britain “covered with rows of metallic windmills”, having exhausted the coal and oil fields. He was the first person to anticipate IVF. A cousin, Graeme Haldane, developed Britain’s earliest ground-source heat-pump.

They were all polymaths, but JBS was the polymath’s polymath. When not busy working out the mathematics of evolution or reciting Homer in Greek, he was originating the ‘primordial soup’ theory of the origins of life, taking the first steps towards the Human Genome Project, and writing children’s books about a wizard with a servant octopus.

The family instinct to write was strong. JBS’s sister, Naomi Mitchison, became the leading female historical novelist of her time and one of the most outspoken women of the Left. An early campaigner for birth control and abortion facilities, she had an open marriage and even wrote about an incestuous encounter with her brother. Despite her anti-establishment stance, she bought an estate in Argyll and lived the life of a Highland laird. Later, she took a young African king under her wing and became ‘Mother of the Tribe’ in Botswana.

Surely the real-life Haldanes deserve their own HBO series. The only trouble is, to do them justice, four seasons would be nowhere near enough.

Richard McLauchlan will be at the Boswell Book Festival on May 13 talking about Serious Minds – The Extraordinary Haldanes of Cloan. Details at www.boswellbookfestival.co.uk