Rudimental's uplifting dance track These Days has been named the most-performed song of 2018 at the prestigious Ivor Novello Awards.

A major international hit, it topped charts across Europe, and became the UK's fifth best-selling single of 2018.

But their prize had to be shared between nine writers - a phenomenon that's become increasingly common.

According to research by Music Week, it took an average of 5.34 people to write last year's Top 100 biggest singles.

That's up from 4.84 in 2017, and 4.53 the year before. So what's going on?

"It's a sign of the times," says Jamie Scott, who wrote the first draft of These Days in a shed at the bottom of his garden.

"You go into a [songwriting] session and there are five people in a session and, if everyone is doing a great job, then there's going to be five people on the credits.

"And if they're not, then next time there are going to be four people in the session."

Scott says songwriting teams have blossomed because streaming services demand a constant supply of new material: An artist who wants to stay at the front of fans' minds needs to put out more new music, more frequently, than at any other time in pop history.

"You need songs out there - literally one a month for streaming," he says.

"It's a business and people want a great product. That's what we're here to do - and that's why you'll find six or seven or even 12 writers on a song."

It can go even higher than that. Anne Marie's 2002 has 18 writers; Drake's Nice For What lists 22; and Travis Scott's Sicko Mode credits a staggering 30 people, each of whom receives a wafer-thin slice of the royalties.

Song 'skeletons'

To be fair, all of those tracks contain samples and/or lyrical fragments of other songs, whose writers receive a mandatory credit in the post-Blurred Lines era of copyright litigation.

But co-writing culture is so ingrained that even singer-songwriters like George Ezra and Lewis Capaldi take a helping hand in the studio, albeit on a more one-to-one basis.

"I often write with other people and I always enjoy it," says James Blunt, whose last album had collaborations with seasoned hitmakers like Ryan Tedder (Adele, Beyonce) and Johnny McDaid (Ed Sheeran, Snow Patrol).

"I still write very much from the heart but it's nice to have someone to show me the elusive fourth chord - otherwise I'd always just be repeating the same three."

For pop star Dua Lipa, working with co-writers helped her learn her craft at the start of her career.

"I was always able to write - essays and poetry - but I never really sat down to write a song," she says.

"So when I started going into the studio, I learned a lot from the co-writers that were coming in to help me - the bones of how to write a proper song.

"But now I feel able to take the lead."

Dua Lipa and Silk City's hit single Electricity credits 10 writers - but she wrote the bulk of the song in the studio with Mark Ronson and Diplo

Songwriting sessions aren't for everyone, however.

After making two records in a Glaswegian basement, pop trio Chvrches attended a songwriting camp to see if it could bring a new dimension to their third album, 2018's Love Is Dead.

"These guys were writing a track and we were bouncing ideas around when a couple of producers came in and kind of sprinkled a chorus on," recalls singer Lauren Mayberry.

"And then they left... We were just like, 'What just happened? Have they gone to the toilet? Are they coming back?'

"But no, they'd left like 'Boof! There's your chorus. Goodbye'.

"That song did not make it any further."

Personal touch

Let's Eat Grandma, whose psych-pop opus I'm All Ears was up for album of the year at the Ivor Novellos, have also shunned writing camps.

"When that many people get involved, everyone is almost competing for their ideas to be heard," says singer Rosa Walton. "It makes it hard to be honest and open."

"If you've got really personal songs, you don't really want to share them with people you don't know that well," agrees her bandmate Jenny Hollingworth, "because then you can't really be yourself."

That's exactly why Olly Alexander (largely) avoided co-writers on Years and Years' recent album Palo Santo,

"I don't really want to sing a song someone else has written," he says. "I have to be the person who writes the lyrics and who writes the top line [melody].

"I wouldn't feel comfortable otherwise."

Dance producer Jax Jones, who's scored top 10 hits with Breathe and You Don't Know Me, says the proliferation of writing credits often obscures the fact that songs originate with one or two people, who will ultimately take the lion's share of royalties.

"When I've had experience of writing in LA, you might get a killer song but as a producer, I'll be like, 'Alright, I need a better part here'.

"And I know someone who's incredible at writing a verse, or a bridge, so I'm going to call them and get them involved.

"But that's traditional record making," he argues. "Quincy Jones works like that, Kanye West works like that. It's amalgamating all these incredible talents, and that's why you get incredible records."

That's pretty much a template for how These Days came together. It was originally written by up-and-coming R&B singer Dan Caplen in a session with the team behind One Direction's Drag Me Down - Jamie Scott, Julian Bunetta and John Ryan.

He sent it to his label, who passed it on to Rudimental. The band liked the song and did some additional production work, earning each of their four members a share of the rights.

Finally, US rapper Macklemore was asked to contribute a guest verse - resulting in a ninth, and final, credit.

Caplen admits the figure looks ridiculous but says the song "needed a little Midas touch to make it what it is today".

 Dan Caplen says any hit single needs the "perfect mix" of hard work and inspiration

In general, however, Caplen prefers to work with a smaller team.

"You know when there's too many cooks in the kitchen? I say three or four maximum," says the 27-year-old.

But the real question is whether the climate of co-writing genuinely affects what we hear.

"A film isn't necessarily more enjoyable if it's based on a true story. Likewise, a song isn't necessarily any better or any more heartfelt, or convincing, because it was written by the singer," wrote Bob Stanley in his peerless history of pop, Yeah Yeah Yeah.

And Natasha Khan, aka Bat For Lashes, argues the modern hit factory isn't too different from the 1960s, when teams like Dozier-Holland-Dozier wrote timeless soul classics in the back room of Motown Records.

"Five writers seems like a lot," she says. "It feels like it's manufacturing something.

"But if a great pop song comes out of it then, why not?"