But the money has not gone on the stars' Winnebagos. It is all up there on the screen, as this sweeping tale recounts, on a grand scale, the dastardly schemes of rival politicians to prevent the immensely popular military leader Julius Caesar (Ciarán Hinds) from seizing power on his triumphant return from victory in Gaul in 51BC. The plotting, back-stabbing and double-crossing makes the Tory leadership contest look like a children's tea party.
But it is not the budget that has been catching the press's attention this week. It is the unexpurgated nature of the series that has set the red-tops' pulses racing. Beside full-frontal screen-grabs from the show, one headline screamed: "10 minutes after the watershed, the BBC's graphic view of Roman life."
For once, you can understand why the red-tops are foaming. Here are some highlights from the first episode of Rome, which starts on BBC2 on Wednesday 2 November. They have been edited to spare the blushes of more sensitive readers.
Within minutes of the start, Atia (Polly Walker), Caesar's breathtakingly manipulative niece, has stripped naked and mounted a diminutive horse-trader. As she dismounts and admits that she has used sex to secure a prized white stallion, she grins, "This was not a hardship for me. I've always found something perversely erotic about goaty little men."
It continues in a similarly graphic vein with unflinching scenes of a shower in a cascade of bull's blood (you'd pay a fortune in certain exclusive Soho clubs to recreate such a scenario), several crucifixions, a corpse having its teeth removed as trophies, and the public rape by Mark Antony (James Purefoy) of a shepherdess in front of both her flock and an entire Roman legion. And so it goes on with a succession of scenes that will have nervous viewers hiding behind the sofa. Caligula had nothing on this.
The thoughtless brutality of the era is underlined when I am on set in Italy, cowering behind the camera, watching in awe as a terrifying cohort of raging, screaming Ulbian horsemen gallop across a plain and ruthlessly scythe down a motley crew of thieves who are attacking the two central characters - a sturdy pair of centurions called Lucius Vorenus (Kevin McKidd) and Titus Pullo (Ray Stevenson). Clad in bearskins and wielding fearsome blades, the horsemen make both me and the ground tremble. Their helmets are adorned with severed human fingers and other male body-parts that I cannot possibly describe in a family newspaper. How's that for authenticity?
Already a huge hit in the USA, where a second series has been commissioned, Rome presents a compelling picture of a culture where casual cruelty is the norm. And yet the makers reveal that they have had to tone down the reality of the savagery. But Jane Tranter, the head of BBC drama, denies that the BBC's vision of Rome is sensationalist. "BBC2 and HBO are grown-up broadcasters. Rome will push all sorts of boundaries. Every time there is sex or violence, it is used to tell the story. It's there because that is how Rome was." She emphasises that no viewer will be ambushed by the gory nature of the show. "There will be plenty of on-air trails and content announcements beforehand."
The film-makers believe we cannot be too judgemental about the Romans, who they say had no concept of shame, so nothing was taboo. They thought nothing of having multiple partners of either sex - there is no Latin word for "homosexuality".
"The mores we have today just didn't apply in those days," says Ray Stevenson. "They didn't see their behaviour as cruelty. In their minds, the Romans were so far advanced of the people they were enslaving that they could do what they liked with them.
The series's creator, Bruno Heller, explains that the brutality of Roman life endowed it with a tremendous vibrancy which lends itself very well to serial drama. "Life back then was lived in very vivid colours. It was very cheap, but for that reason it was also lived to the full." This is mirrored in the down-and-dirty look of the drama. The blood-spattered buildings are far from the pristine white-marble portrayals of Rome we are used to.
April Ferry, the costume designer, declares that "our Rome is like modern-day Bombay - intense, dirty, dense, funky. Also, our Romans are a lot grubbier than usual. This is an ancient city on the brink of collapse, rather than a serene and noble mausoleum."
The producers constructed a five-acre replica of Ancient Rome on the expansive back-lot at Cinecitta, on the outskirts of the Italian capital. The life-sized recreation of the Forum, with the Senate, the Treasury and the Temples of Jupiter, Venus and Vesta, is a thing of gigantic beauty. The producers hope it will remain standing for at least five years, so it is built out of solid concrete. The star of this show is Rome itself.
As well as being a feast for the eye, Rome provides food for thought. It offers, for example, many modern-day political echoes. Viewers will not have to look far to find parallels between Rome then and the US now. McKidd, who has headlined in films such as Trainspotting and Kingdom of Heaven, says that "Rome developed its power and influence across the world. Once the Romans had got a stranglehold on a country and reaped the benefits, they just moved on. And as soon as there was a sniff of anything that Rome didn't like - boom! - they'd lay waste to your country. The parallels with the US today are scary."
'Rome' begins on BBC2 at 9pm on 2 NovemberReuse content