Television is a glutton. Give it a hit and it wants more and more of the same until it makes itself sick. So when, almost a decade ago, Downton Abbey came along and showed that a soapy period drama could command a global audience, TV wanted more of it.

It got six series and was followed by a stream of fast-paced period pieces, including Victoria, the rebooted Upstairs Downstairs, Poldark and Outlander. The man who created Downton, Julian Fellowes, went off to write a novel. Called Belgravia and published in 2016, it was about the birth in the early 19th century of the stucco-fronted “city of the rich”, built by the Cubitt brothers in what was then marshland southwest of Mayfair.

The book appeared in instalments online, as if Dickens had been given a laptop and a blog. It was hyperlinked and multilayered: there were pictures of the characters, and you could look up the role of a tweeny (the nickname of a between maid, whose responsibilities were split between those of a butler and a cook) and find out what a housekeeper would have earned in 1842.

“I was rather entertained by the whole concept,” Fellowes says in his detached, uniquely Fellowesian style. “I thought it seemed an attractive marriage of the past and the future.”

A Novel Idea

As it happened, a novel delivered by instalment fitted the episodic style of a TV serial to perfection. “I suppose, in a way, I had half written it hoping it would end up on the screen,” Fellowes says, as if we couldn’t have guessed. When Gareth Neame, his long-time producer at Carnival Films, received the book, there was an inevitability about what happened next.

“I read the whole novel and immediately took it,” Neame recalls. “I thought it was almost a perfect piece of ‘Fellowesiana’, and if I didn’t turn it into a limited TV series, there would be lots of other people queuing up.”

British author Julian Fellowes.

So, four years after the publication of the book, Belgravia comes to ITV, Downton Abbey’s former home, next month. A six-part miniseries starring Tamsin Greig, Alice Eve, Philip Glenister and Harriet Walter, it tells the story of two London families in the mid-19th century, the Trenchards and the Brockenhursts, one nouveau riche, the other ancien régime. The Trenchards, Anne and James (Greig and Glenister), are the new money, their fortune made in the construction business.

“James Trenchard is the Alan Sugar of his day,” Glenister says. “He started off with quite humble beginnings and basically worked his way up to become a wealthy, successful property developer.” Working with the Cubitt brothers, Trenchard has built the terraced streets of Belgravia, a wonderland for the wealthy. The Countess of Brockenhurst (played by Walter) represents the established aristocracy, elegantly dismayed by parvenus like the Trenchards, who inch into their parlours without wiping their feet.

Belgravia tells the story of two London families in the mid-19th century, the Trenchards and the Brockenhursts, one nouveau riche, the other ancien régime.

Belgravia begins with a flashback to a real-life event: the Duchess of Richmond’s fabled ball in Brussels in 1815. It took place on the eve of the battle of Waterloo, and Fellowes, with characteristic historical dexterity, uses it as a means to bring his two families together. A short-lived affair between the Trenchards’ daughter and the countess’s son conspires to leave Anne and the countess with an orphaned grandchild. The countess knows nothing of the boy until an encounter with Anne 25 years later leads to the secret being revealed. The boy is called Charles Pope, and he is making a name for himself in business. Like Pip in Great Expectations, Charles grows up to find himself squabbled over by two very different families.

“It’s about codification in society,” says Tamsin Greig. “Anne Trenchard is a picture of the changing face of money, but she and her husband have no real standing. Now that they have wealth, they have access to houses they wouldn’t normally have any right to enter. I think access and the power of access is something that actually drives a lot of what we do.”

The success of last year’s Downton Abbey feature film — most critics agreed it was like an extended episode of the television show, aimed squarely at bereft fans — showed that there remains a Downton-shaped hole on television. Is this the series to fill it? “Belgravia is also accessible and popular, and speaks from the heart, but it does it in quite a different way from Downton,” says Neame, who has produced the show. “It is not an episodic pop soap. This is very much a limited series, with a beginning, middle and end. It’s six hours with this group of characters.”

“I was rather entertained by the whole concept,” Fellowes says in his detached, uniquely Fellowesian style. “I thought it seemed an attractive marriage of the past and the future.”

The truth, though, is that Belgravia doesn’t want to be too different from Downton, one of British television’s greatest hits. “Obviously it’s in the same milieu,” Neame concedes. “It’s a period setting, and it has a lot of the characteristics, the themes, the subjects Fellowes has written about — be that class or a comedy of manners, or people who are inside the club and people who are outside the club, but want to be in the club.”

There are also several of the same tropes that underpinned Downton, including a woman’s love for her children and what it’s like to lose a child. Lady Edith Crawley spent most of the fifth series of Downton popping down to the local farm to snatch glimpses of her secretly fostered son. In Belgravia, Anne Trenchard and Caroline Bellasis, the Countess of Brockenhurst, are united in the fact that they lost a daughter and son respectively, many years previously.

“I think that Julian putting those two women at the heart of it all is very interesting,” Greig says. “They are from different backgrounds, but both have lost children and that brings them together. It’s about the democratisation of loss — everybody experiences grief. It’s these two women with access to that emotional world who open up this story.”

Where Women Rule

As he did in Downton Abbey with the Dowager Countess (Maggie Smith) and the Countess of Grantham (Elizabeth McGovern), in Belgravia Fellowes gives equal attention not merely to women per se, but to women of different generations. Some of the best scenes involve Anne and the countess in quiet, highly charged two-handers over afternoon tea — which was, Belgravia teaches us, a newfangled and highly fashionable ceremony at the time.

Tamsin Greig and Alice Eve in Belgravia.

Greig gives a deft performance that will come as no surprise to those who have seen her stage work; if you only know her from Friday Night Dinner or Episodes, it is a revelation. “Of course Belgravia is like Downton Abbey in the sense that it’s made by Carnival, it’s written by Julian Fellowes and it’s got corsets in it,” she says. “But just keep watching and see what happens — I think it stands alone.”

One key difference, according to Fellowes, is that it’s slightly gloomier than Downton. “Downton was, on the whole, a sunny place where people lived generally sunny lives, if not entirely. Whereas we pitch darker in Belgravia. It has a sadness. I think also it’s quite informative about the kind of influences that were swirling around in early Victorian London.”

There are also several of the same tropes that underpinned Downton, including a woman’s love for her children and what it’s like to lose a child.

That sense of the history behind the fiction is something else Fellowes always brings to his work: his dramas wear their learning lightly, but are learned nonetheless. “The projects I’ve done with him so far have all been varied,” Neame says, “but in every case he has a deep knowledge of the period. He’s a historian. He’s genuinely intrigued by the way human beings relate to one another.”

Neame’s work with Fellowes has also been hugely successful. Indeed, Fellowesiana, as he calls it, has become a winning seam that runs through much of pop culture. Since Fellowes won a best original screenplay Oscar for Gosford Park in 2002, his work has been a success wherever it has appeared. He wrote the screenplay for The Young Victoria and the librettos for the musicals Mary Poppins and School of Rock, both of which are still running; his novels Snobs and Past Imperfect were Sunday Times bestsellers; and there was the Downton Abbey film. (Don’t rule out another one.) This year, on television, in addition to Belgravia, there will be The English Game, a Netflix docu-drama about the birth and rise of football, and The Gilded Age, about New York City in the late 19th century, on HBO. As unlikely as it may seem given Fellowes’s love of history, at 70 he is very much the coming man.

“I always used to have a thing I called the Downton argument,” he says. “The Downton argument was between two characters, where you would change your mind as to which side you were on. I hope people watching my work will start with their initial prejudices, whatever they may be, but during the course of the story, if they don’t completely change their mind, they will nevertheless open up a bit to the possibility of the other side of it.”

Most dramatists would hope for the same. The difference with Fellowes is that the prejudice he tends to undermine is people’s perception of the upper classes as unworthy of dramatic interest. “I remember some head of drama at the BBC in the 1970s or thereabouts saying, ‘Only the working class have emotions.’ You just think, ‘Wake up, baby.’ But people believe these things. They hear them repeated so often that they believe them. Of course they’re a complete nonsense. I suppose, if I have a crusade, it’s to argue against types.” That’s one reason why his period dramas have tended to end up on ITV and not the BBC, he says.

“I don’t want to get into a BBC fight, but they are interventionist, and want their drama and their other programmes to reflect their own position on various issues. That means that if you disagree with the BBC, then you’re not the writer for them, really.”

As Fellowes sees it, he’s not merely drawing parallels between different eras, but showing that even in times of great change, people don’t really change at all. “I suppose, in the end, one of my core beliefs is that, on the whole, people of all types, classes, periods, nationalities, background, whatever, have very similar urges and desires and requirements and so on,” he says. “I don’t think people in 1840 wanted things that are very different from the things we want.

“They lived differently, of course — it would seem to us rather tiresome to have a house with 16 servants wandering around. Nevertheless, it doesn’t alter the fact that we still want to be rich, and they wanted to be rich. They wanted to make a good marriage — so do we. We do these things for different motives — so did they. They worried about their children — so do we.”

Lineage is at the heart of the story in Belgravia and, though issues such as inheritance and primogeniture may seem at best peripheral to modern life, Greig says she thinks that once again Fellowes has hit on a subject we can all relate to. “We long to know where we come from. Children delight in stories of, ‘Tell me about when you were young. Tell me that story about Grandpa.’ They long to know their lineage, where they fit into the big narrative.

“I think Julian does have that eye and that fascination for where we’ve come from that reflects on where we are now — and then, potentially, where we’re headed.”

Fellowes is well aware that his period drama is timely. “There was a truism in the industry about 10 years ago that period drama was finished — that no one was interested in the past any more, the audience had evaporated and it was done. That was why, when Peter Fincham [ITV’s former television director] gave us the commission to write Downton, a lot of people thought he was crazy — it was clearly going to be a very expensive show and they thought he was mad to be risking it.”

Fincham’s punt on period drama being just the thing for a 21st-century audience turned out to be completely right, and Fellowes turned out to be its best exponent. Now he just has to repeat the trick.