What links Downton Abbey and new ITV drama Tutankhamun? Highclere Castle and the history of the 'pharaoh's curse'

It was with this razor that Carnarvon cut an inflamed mosquito bite while shaving, just after making the most important archaeological discovery of the 20th century.

The Earl of Carnarvon in 1923

The five floors of Victorian neo-gothic pile above us are famous around the world from Downton Abbey. The series was filmed at Highclere from 2010, but the house has other, darker, claims to fame.

The present eighth Earl of Carnarvon, George Herbert, and his wife Fiona are walking me through what used to be the wine cellar, now home to Highclere’s Egyptian collection. It is one of the strangest and – now that all the visitors have left – spookiest small museums in Britain.

When Shirley MacLaine came here to film her Downton Abbey scenes as Cora’s mother Martha Levinson, she was alarmed to see pictures moving on the walls and reported a strange atmosphere in the house. Feeling a slight shiver when passing an ancient casket, I know how MacLaine felt when she revealed, wide-eyed, to American reporters, “They have the tomb of King Tut in the basement!”

Lord and Lady Carnarvon don’t actually have King Tut, better known as Tutankhamun, down here, but they do have the family’s surviving items from the grave of the 19-year-old boy pharaoh, buried in Egypt some 3,300 years ago and rediscovered by the fifth Earl and the archaeologist Howard Carter in 1922.

They also have artefacts from other digs during the Earl’s time in Egypt in the early 20th century – cartouches, delightful figurines, a marble table for religious libations and a (thankfully) empty sarcophagus, “The mummy bit is in Cairo,” says Lord Carnarvon.

For much of his 56 years the fifth Earl had dedicated himself to an English aristocrat’s usual pleasures: driving fast cars, painting watercolours, amassing a 3,000-strong collection of erotic photography and – vitally for a man with the upkeep of Highclere Castle to pay for – finding a very rich wife.

Sam Neill as the Earl of Carnarvon in ITV's Tutankhamun

Carnarvon chose Almina Wombwell, the illegitimate daughter of Alfred de Rothschild, an immensely wealthy director of the Bank of England. Almina bore him a son, Henry, in 1898, and a daughter, Evelyn, in 1901.

Carnarvon had taken up Egyptology after wintering in Cairo as he recovered from a bad car crash. He’d employed Arab digging teams and worked in the Nile delta and the Valley of the Kings, but the results of their efforts had been largely unspectacular.

Then, in 1907, he met Howard Carter, an obsessive, brilliant but socially clumsy East Anglian who had fallen foul of the authorities in then British-controlled Egypt.

Carter, the Earl gambled, would find him treasure, and year after year Carnarvon returned. Evelyn, who pressed Carter constantly to tell her more about the mysterious boy king they were hunting, often accompanied him.

The heat, the sand, the tents… it would only have been reasonable, as the new ITV series Tutankhamun shows, for Carter (Max Irons) and Lady Evelyn (Amy Wren) to have fallen into each other’s arms.

“My goodness, no,” says Lady Carnarvon, taken aback at the suggestion. “There is no evidence for a romance between them whatsoever. Carter was absolutely dedicated to Lord Carnarvon [played in the drama by Sam Neill] and to their work, nothing else mattered.”

Carter was also the son of a Norfolk livestock artist – not marrying material for the aristocracy. Just in case, Evelyn was later married off to Brograve Beauchamp, a future baronet and Conservative MP.

Finally, on 26 November 1922, the Earl’s gamble paid off. Twenty invited guests and a hushed group of Arab workers looked on as Carter and Carnarvon prepared to open up the final wall separating them from what they believed were the intact burial chambers of Tutankhamun.

It was the pinnacle of the aristocrat’s eventful life. Carter’s years of struggle and expertise had brought them to this point, and he was first to go in. What the 48-year-old saw when he lifted his torch and looked around has entered popular legend.

Howard Carter (left) and Arthur Callender (played by Adam Neil in the ITV series) in the tomb

“Emerging slowly from the mist, strange animals, statues, and gold,” he would write. “Everywhere the glint of gold… Wonderful things.”

There were jewels, protective figurines, cats, daggers with a blade made from a meteorite, jackals, chariots, statues and piles of ivory. The burial chamber with the pharaoh’s gold sarcophagus and famous mask would be opened a few months later.

It was an astonishing triumph for Carter and Carnarvon, and within days they were the two most famous men in the world. Yet five months later Carnarvon was dead.

The mosquito bite the Earl had cut with his razor became infected. Blood poisoning set in and then, pre-antibiotics, pneumonia, to which he succumbed in Cairo’s Continental-Savoy Hotel on 5 April 1923.

A frantic international press immediately decreed that the Earl had been struck down by the curse of the mummy he and Carter had disturbed. Hadn’t a cobra, the snake that represented kingship in ancient Egypt, entered Carter’s house and killed a caged canary shortly after the tomb was opened? Didn’t young Lord Henry, back home in Highclere, report that the family dog had died at the very moment his father had?

The world had just come out of the Great War that had killed some 16 million people and a Spanish flu pandemic that carried off 25 to 50 million more. Death was on people’s minds.

This was also a story that emphasised Britain’s imperial reach. The empire had reached its zenith – Egypt was slipping from its grasp, torn by nationalist rioting, and next-door Palestine was already proving beyond Britain’s ability to govern fairly.

Who can blame the British if they gilded the lily when it came to the discovery of Tutankhamun and his fabulous hoard by an aristocratic adventurer straight from the golden days of empire – especially when it cost him his life?

Carter was devastated by the Earl’s death: “My beloved friend and colleague Lord Carnarvon, who died in the hour of his triumph”, he declared. The Earl’s widow Almina sold the majority of his collection to the Metropolitan Museum of Art in New York in 1925 (the same year that Tutankhamun’s coffin was finally opened and the death mask removed, which involved severing the pharaoh’s head from his body), but Carter still came to the house, cataloguing what remained.

And the legend of the curse continued to grow as the people associated with the find began to die. Carter was 64 when he died of leukaemia in 1939, yet this was taken as evidence of the malign powers at work. Carter left behind boxes of relics, statuary and funerary objects, all of which were a constant reminder to the sixth Earl that his father had been the victim of a curse.

Howard Carter in the early 1920s

“His father had died out there in Egypt, when he was still relatively young,” says Lord Carnarvon. “I think it was very traumatic for him.” Henry hid the artefacts around the house but he could never escape the Tutankhamun story, even in his old age.

It had been a sensation in the 1920s; it was a sensation again in 1972 when the British Museum’s Tutankhamun show broke box-office records and caused huge queues in Bloomsbury.

Once more the beauty of the finds and the mystery of the curse exacted their pull on the public imagination. Yet nearly a century of study of more than 4,000 objects brought out of the dig site has failed to produce any sign, warning or threat whatsoever. It’s as if the curse didn’t exist at all, but had been invented by editors who wanted to sell newspapers.

“Exactly,” says the present Earl. “I have always felt that there was nothing to it. I have been to Egypt many times and I have always been OK.” When Henry died in 1987, his son the seventh Earl – another Henry Herbert – and the present Lord Carnarvon searched the house. “We found things between two cupboards in the living room and elsewhere, in little Egyptian cigarette boxes and tins,” he says.

“This extraordinary head of Tutankhamun’s grandfather, the famous pharaoh Amenhotep III, was in the back of a scullery.” Just hidden away? “Yes, grandfather had a strange view of his father’s death – he really did think he had brought bad luck on himself in some way or another.”

Lord and Lady Carnarvon laugh, so do I – but as they make their way to the door and turn off the light, I make sure I’m right behind them.

ITV's Tutankhamun begins Sunday 16th October at 9pm on ITV