A tour of Bridgerton's filming locations - just in time for season three

The magnificent Georgian-era smirk of the Royal Crescent in Bath embraces and frames the road that curves around its 30 front doors. Built in 1775, the Royal Crescent is a terrace of 15-metre-tall townhouses designed to resemble a palace. There were servants' quarters in the basement and servants' bedrooms in the attic, with the storeys between occupied by wealthy visitors to Bath's famous spa.

From the front, at least, the Royal Crescent seems unnervingly perfect, as if it has survived the centuries unchanged.

It also looks like a movie set - which, of course, it is.

Bath in Somerset is a much-filmed city, the 18th-century backdrop to 21st-century movies including Persuasion, Tess of the D'Urbervilles, Vanity Fair and The Duchess. Every year, about 100 days of filming take place in Bath, and the most popular location is the Royal Crescent.

Much of the first season of the smash-hit Netflix series Bridgerton - set in Regency England at the tail end of the Georgian era - was shot in Bath. The Royal Crescent appears two minutes into the opening episode. The cars that line the road today are gone, replaced on screen by horses and carriages. Drivers become coachmen and footmen. Everything is as it once was.

Except that the yellow parking line remains clearly visible in the corner of the shot.

It's a tough job, making a historical drama.

On the upside, the first season of Bridgerton was watched by 82 million households internationally in its first 28 days on Netflix, making it the most popular TV show in world history.

I am gazing up at the Ionic columns of the Royal Crescent on a crisp autumn afternoon, learning about Bridgerton and Bath from my uncommonly knowledgeable Blue Badge guide, Fred Mawer.

A few months earlier, I had been meandering through Bath looking for a good pub (spoiler: there are loads of them) when I passed three separate huddles of travellers taking Bridgerton-themed walking tours.

I wondered what their serious-looking chaperones could possibly be telling them.

Which is why I came to hook up with Mawer for his engrossing and amusing Bridgerton and More tour, but I soon become suspicious of my guide: how can he possibly know so much about, well... everything?

Mawer does not advertise the fact, but he has a degree in Latin and Philosophy from Durham University and he accepts that he is perhaps "not the typical Bridgerton fan".

"You know when you're doing a pasta dish for kids," says Mawer, "and you hide the vegetables in the pasta? That is what my Bridgerton tours are like: I hide nuggets of history."

He tells me that the Royal Crescent was the first crescent built in England. At first it was simply called "The Crescent", because there were no others.

And, like a movie set, the Royal Crescent is a facade. Georgian architects were only commissioned to design the front of buildings, so much of Bath - including the Royal Crescent - looks a mess from behind.

Netflix's Bridgerton is based on a series of eight novels by US romance writer Julia Quinn. The first season, The Duke and I, is an adaptation of the book of the same name. The second season mirrors Quinn's second Bridgerton novel, The Viscount Who Loved Me. The third season, which is being released on May 16, jumps to the fourth book, Romancing Mister Bridgerton.

The overarching theme of the novels is the relationship between the Bridgerton and Featherington families, whose on-set townhouses neighbour each other on the Royal Crescent (although, according to the storyline, it is supposed to be Mayfair in London).

The Featheringtons live at Number One Royal Crescent which today is a museum of grand Georgian life. Only the (CGI-enhanced) exterior shots were in Bath: the interior scenes were filmed in Hatfield House in Hertfordshire.

Mawer says it was "really easy" to look in on the filming of season one "because nobody had heard of Bridgerton, and they weren't particularly prescriptive about being able to watch what was going on". During seasons two and three, the filmmakers were far more circumspect, as they were worried about being swamped by crowds. Season two was codenamed "Waterloo", a word that appeared on all the diversion signage to throw fans off the scent. Burly men in hi-vis vests warned people to get back from the set and put away their camera-phones.

If you haven't seen Bridgerton (in which case, it's only a matter of time) it's a traditional costume drama updated to include a multi-racial cast, a soundtrack of music by Ariana Grande and Rihanna, lots of sex and a bit of bare-chested, bare-knuckle boxing - none of which are found in, for example, the work of Bath's greatest writer, Jane Austen.

Mawer leads me to Bath's enormous Assembly Rooms, where public balls were held in the 19th century and private balls were staged for Bridgerton. The balls were designed to match eligible women with wealthy and titled bachelors. Halfway through the dance program, the guests would retire to the tearoom for an elegant cuppa (as tea, imported from China, was regarded as a luxury in Regency England). The dances in Bridgerton were filmed in the tearoom, rather than the ballroom, to take advantage of the tearoom's arresting double arcade.

The Assembly Rooms' nine chandeliers are the most valuable Georgian chandeliers in existence, and in Bridgerton they lend their dazzling illumination to Lady Danbury's ball. The filmmakers needed the lights in the shot, but the lamps hung too high from the lofty ceiling. Luckily, the chandeliers are hoisted by pulleys, as they originally held candles and the candelabra had to be lowered for lighting. For Bridgerton, they were brought halfway down so the cameras could film through them.

Lady Danbury's house is played by the original wing of the Holburne Museum, an art gallery that was dressed up as a stately home for season two and bedecked even more elaborately for season three. The museum sits inside Sydney Gardens - which, like the city of Sydney, was named after the Whig politician Thomas Townshend, 1st Viscount Sydney.

Bridgerton also filmed around the perfect Georgian Abbey Green, today a prime busking spot. Mawer says he is often asked if he knows any of the cast of Bridgerton. "I met Colin's mother," he says (meaning he met the mother of actor Luke Newton, who plays Colin Bridgerton in the show). "She came on a tour. I was obviously more excited than she was."

Although Mawer's contacts do not stretch to the stars, he can boast of extensive access to his wife's nephew, George.

George worked as a "dogsbody" for the production in Bath - generally keeping people like his uncle away from the filming - "but he had a slightly more interesting role in Abbey Green," says Mawer, "which was to pay the street musicians not to play.

"He'd be given the Bridgerton credit card and first thing each morning he'd head off to the nearest ATM, take out a big wadge of £10 and £20 notes, and give them out to the buskers. He was a very popular chap. The going rate for the buskers not to play was £50 for every 45 minutes."

Outside the Abbey Deli, we bump into the owner, Nicky Ison, and make an unscheduled refreshment stop. The Abbey Deli (actually more of a café) doubles as Bridgerton's Modiste boutique, where a cockney dressmaker pretends to be a French lady to impress her aristocratic clientele. The panelled room where my guide and I share a pot of tea is the chamber where the women of Bridgerton try on their dresses.

"Based on my research," says Mawer, "Bridgerton got the ballgowns pretty close to correct - very low cut: balls being all about marriage, ladies were supposed to show themselves off to best effect."

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By contrast, he says, "day-to-day wear for the ladies in Bridgerton is much too vibrant, much too colourful. By the Regency period, the aristocracy had started to dress down a bit. We'd had the French Revolution in 1789 and, right across Europe, the aristocracy didn't want to be quite so visible."

I sense a nugget in my pasta here.

"If you think of one item of clothing you'd get in a Jane Austen adaptation, you'd probably think of a bonnet," says Mawer. "What you don't get in Bridgerton is bonnets. They're banned because they're regarded as being too old-fashioned."

The men, however, all look the part. "The leading arbiter of fashion was a friend of the Prince Regent, Beau Brummell," says Mawer, "who came up with this very dapper style of dress - trousers, tailored waistcoats, cravats, top hats: Bridgerton gets that pretty spot-on."

The Abbey Deli caters to Bridgerton fans, not only at the tables - "we are inside Bridgerton now," Mawer tells me - but also with a range of souvenirs dedicated to Bridgerton gossip monger Lady Whistledown (T-shirts, sweatshirts and cushion covers with the legend "Lady Whistledown, spilling the tea since 1813").

I never ask Mawer what he really thinks of Bridgerton. I was tasked with reviewing the first book in Julia Quinn's series for a national newspaper and I said it was worthless. I enjoyed the Netflix production both as spectacle and as drama but, when I think about it now, I got more out of Mawer's tour than either the book or the show.

What: Two-hour Bridgerton walking tours of Bath with professional tour guide Fred Mawer (fredmawertours.co.uk). Mawer's tours visit all the locations in Bath where Bridgerton was shot and also offer insights into various movies filmed in the city.

How much: £130 ($247) per group, with a maximum group size of 20.

Explore more: fredmawertours.co.uk; visitbath.co.uk