Writer Tom Bidwell had been pitching his idea for The Irregulars for 10 years. And, with a Netflix series finally in the bag, it paid off in the end.

The story follows a gang of troubled street teens who are manipulated into solving crimes for Sherlock Holmes and Doctor Watson.

Set in Victorian London, the eight episodes are spooky, thrilling and mysterious, and feature a cast brimming with young stars who you're going to be seeing a lot more of in the future.

Then there's the remarkably fresh depiction - by Henry Lloyd Hughes and Royce Pierreson - of one of the most beloved relationships on screen: Holmes and Watson.

"I loved being able to get under the hood, I suppose, of such a well-known character; really explore an emotional realm that I don't think we've necessarily plumbed those depths of before," suggests Lloyd Hughes, 35, a London-born actor, who you'll recognise from Killing Eve and The Inbetweeners.

"The dynamic of Sherlock and Watson is usually set up so that it's quite slick, and to pull that apart at the seams - there was something really satisfying about, from an actor's point of view, getting my teeth into that."

Intrigued? Here, we chat to the show's main cast about what else viewers can expect.

SETTING THE SCENE

The series is loosely based on the street urchin gang called the Baker Street Irregulars, who appeared in several of Arthur Conan Doyle's Sherlock Holmes stories.

The five misfits we follow are Bea (Thaddea Graham), Jessie (Darci Shaw), Spike (McKell David), Billy (Jojo Macari) and Leopold (Harrison Osterfield).

We see the youngsters solving horrifying crimes with a supernatural edge - and then, they are forced to come together to save not only London but the entire world, when a dark power emerges.

"One of the things that really sets Irregulars aside from previous things set in the Sherlock Holmes universe is the fact that it talks a lot about grief and it talks a lot about emotional health and mental health", notes Sex Education star Macari, who also jokes about how "ripped" he had to get for the role.

"Currently, there is a huge focus on mental health - a bigger focus than I've ever seen before, which is fantastic - and I think that's why now might be the right time for The Irregulars."

SIBLING LOVE

For Graham - who's known for Netflix's The Letter For The King and BBC drama Us - what she loved about playing Bea was the bond her character has with her little sister, Jessie.

"I think that's really lovely to see on-screen, at the forefront of something," she follows.

The star - who was born in China but raised in Northern Ireland - adds: "The most challenging thing was not necessarily something to do with Bea, but it was over a year that we shot Irregulars, so just the stamina was quite difficult to maintain."

There was a lot of dark material to film, too. But Liverpudlian Shaw revelled in exploring the depth within her character.

"Probably my favourite thing about playing Jessie was the fact she had so many different sides; she had a really kind of fun, comical side, when she talks about shenanigans, and then obviously she has quite deep emotion in the show," says the star, who's previously appeared in The Bay.

COMPLEX FIGURES

All the characters in The Irregulars will draw you in, including Leo, who Osterfield - who had a role alongside George Clooney in Catch 22 - explains "has always got these internal battles going on".

"He's putting on a brave face, which has been a really fun thing to play because the words might be saying something but inside, it's a very different feeling."

Then you have Spike, who's the "cheeky lad of the group", according to David.

"He'll try and do anything to put a smile on his friends' faces while they're going through all these really dark times and depressing moments," continues the star, who started his own show on YouTube as a young teen.

"It was great to play a character like that, to be able to come in and have that freedom to be loose and to create."

Watson, meanwhile, is a character that Cornishman Pierreson, 31, has loved for many years, having read Conan Doyle's books growing up.

But The Witcher and Line Of Duty star wanted to explore a "flipside" to the character.

"I thought, 'Let me depict Watson as this drifter, this traveller, this guy with a history', and we discover through the series the demons he's been dealing with...

"He became this chancer, this survivor who's bounced around through life and various places in the world and he's just adapted to whatever situation he needs to adapt to survive."

FRIGHT NIGHT

Be prepared - there are many creepy, jumpy moments whilst watching The Irregulars (expect incredible prosthetics and special effects).

And it seems there were some "freakish moments" while on set too, with David recalling filming in one location which used to be a children's hospital.

"One of the ADs (assistant directors), Eric, was showing me around, and he took me in this room, and it had all of this stuff - old fashioned buggies and cots. It was a very, very eerie experience."

"Apparently it's one of the most haunted buildings in the country," chimes in Macari.

As for whether they're fans of the horror genre themselves, it turns out some of the cast are actually self-proclaimed "scaredy-cats"...

"It was such a staple, going round to your friend's house and having a sleepover and everyone wanted to watch a scary movie," says Graham, laughing.

"They'd put it on the TV and my workaround would be I'd only stare at the bottom corner of the TV. And then when they reacted, I'd be like 'Oh yeah, that was scary'- but I wasn't actually watching the movie."

"I would be the one who went to sleep the first because I'd be like, 'This isn't right, this is a 15 [film] and we're only 12 so, no," quips Shaw. "I was a bit of a goody-two-shoes I think!"

The Irregulars launches on Netflix on Friday.