Political intrigues, murderous ambitions, debauchery, intrigue and betrayal. No, it’s not a new series about Boris Johnson in Number 10, but a revival of the 12-part BBC series I, Claudius that first aired in 1976. Based on two books by the First World War poet Robert Graves, it features a slice of imperial Roman history centred on the testimony of Claudius.

He’s regarded by his noble family as a no-hoper, a weak fool who will play no role in the elite power struggles. But he survives the bloody fallouts and dynastic ­battles to become the fourth emperor of Rome.

Claudius records the other emperors’ lives—from the clever Augustus and his brutal wife Livia to the vicious Tiberius and the wild excess of Caligula. I remember watching it the first time round, and it was quite a shock, given the generally staid tone of British TV. 

In the first episode, Julia the elder and Antonia are having a massage, during which they talk about the preference of Julia’s new husband, the future emperor Tiberius, for anal sex.

Both then and now the ­production looks almost laughably amateurish in parts, with outrageous wigs, creaky scenery and bad make-up. There was no money to build an outdoor set, so it was shot in a couple of ­frequently-redressed rooms in Television Centre. It often feels like a stage play.

Constant technical ­problems bedevilled the production. But Graves was unperturbed. “I’ve communed with Claudius,” he said at the time, “and he ­reassured me that this would be a great success.”

Graves was a very complex character, heavily affected by the horrors he witnessed in the 1914-18 war. His memoirs detail British soldiers shot for “cowardice” and the murder of German prisoners of war.

Afterwards he was plagued by nightmares and ­hallucinations. “Shells used to come bursting on my bed at ­midnight. Strangers in daytime would assume the faces of friends who had been killed,” he wrote. 

Writing about Roman emperors probably felt like a relief for him.  In the TV series some scenes culled from the ancient authors that Graves relied on needed toning down. 

One example is when Caligula, channelling the god Jupiter, slices open his pregnant sister-wife Drusilla to eat their unborn child.

Disturbed by Drusilla’s dreadful screams, Claudius knocks on the door to the imperial bed-chamber, opened by Caligula with his mouth dripping blood. He tells his uncle, “Don’t go in there.” So, of course, he does–only to turn away in horror from the sight that greets him,

There’s some great acting. The title role made Derek Jacobi a star, although he claimed that Charlton Heston, Alec Guinness, Michael Gambon and even Ronnie Barker were above him on the BBC’s wish list.

Initially critics tore it apart. “It was so badly received in its first two weeks,” recalled Sian Phillips, who played Livia, “because it was so different.” The Guardian—which now says it is a masterpiece—­loftily proclaimed, “There should be a society for the prevention of cruelty to actors.”

The show was a modest ratings hit for BBC2 with an average audience of around 2.5 million an episode. It was soon re-evaluated and won greater popularity with repeat transmissions. Because of its success, the BBC plunged into other historical shows, such as the 1981 series The Borgias and 1983’s The Cleopatras.

But although both were far more slick, they didn’t have the source material, the writing or the acting of I, Claudius.

Enjoy the re-run.

Episodes of I, Claudius are showing now on BBC Four, and most are already available on BBC iPlayer