Oscar joined the Strictly staff when he was 18 expecting it to be warm and welcoming, like he had seen on TV.

But the reality was very different.

As a runner on the show, he was shouted at and called stupid, he says. Once, a celebrity screamed at him, getting so close to Oscar's face that he could feel spit, he tells BBC News.

"The whole culture was toxic, particularly for junior staff," he said.

The row over Strictly in recent weeks has focused on celebrities and their professional dance partners.

The show's production staff have been largely forgotten in the debate. These are people like runners, who do the unglamorous, lower-paid work. Often, they don't have a voice.

BBC News has spoken to 15 current and former members of staff on the show about its culture behind the scenes. All wanted to remain anonymous for fear of career repercussions.

Some told a positive story of dancers and staff who were kind and respectful to them. But others painted a picture of a workplace in which workers were bullied and junior employees were shouted at by professional dancers.

"I think it’s awful for the celebrities who suffered, but I think for the crew it’s a much bigger problem," a former TV package editor on Strictly, Jane, told us.

A BBC Studios spokesperson said they don't recognise the claims, nor will "hundreds of production personnel" who have worked across the two decades the show has been on air.

They apologised if anyone didn't feel able to raise their experiences at the time, adding: "The welfare and safety of our crew on each series has always been, and remains, our utmost priority.”

The dance world is famous for its intense training, and exacting standards.

With Strictly, you have a weekly national TV show, which involves tight deadlines and the need to have a dance routine perfected by Saturday night.

When you put those two things together, you can see why it might result in a pressure cooker environment.

Jane worked on Strictly's spin-off show, It Takes Two. The same crew shot the packages for Strictly as for It Takes Two, so she would hear of what was going on on both shows.

“When you’re in the edit suite, you’re like a therapist," she told BBC News.

"Crew would come in and tell me about their experiences as we cut their ."

Jane says junior staff would say they'd experienced "verbal abuse" from some of the dancers, including "shouting, screaming and being insulted, to an extraordinary level".

"Whatever mood the dancers were in, would dictate how your day would go," she said.

BBC Studios noted that Jane's testimony is based on rumour, which, it said, "is not unusual in the industry, particularly around successful long running shows".

But what Jane overheard is echoed by Oscar's actual experiences.

"Producers would be drinking and partying, while everyone else was running around stressed out," he said.

On one occasion, he asked someone for a handover, but says he was called "stupid" for asking. "It was bullying behaviour," he said. "I felt sick, and couldn’t sleep or eat."

Oscar says his worst experience involved one of the celebrity contestants on the show.

He describes them as flying into a rage when he passed on simple instructions to them before a show. He says nothing he did would appease the celebrity.

"He was shouting and he was so close up in my face, I had to close my eyes as his spit flecks were hitting me," he said.

"The fact it was in front of everyone made me feel awful and helpless. People were stopping in the corridor to catch a glimpse of what was happening."

The celebrity later apologised to him. But Oscar said it never should have happened in the first place.

"I remember thinking that this was it, and I couldn't take it anymore," he added. "It was the final straw for me."

Oscar left the show shortly after.

Strictly - with its bright lights, sparkles and sequins - has been running for almost 20 years.

But recently, the shine has come off the show.

A number of former celebrity contestants - including Amanda Abbington, Zara McDermott and Laura Whitmore - have made allegations about the way they were treated on the show.

Paralympian Will Bayley has also spoken out about his experiences, after he was injured following pressure to do a jump.

And what we have heard from former production staff, indicates there could be a wider problem with the workplace culture.

Others have described more positive experiences. A choreographer who we're calling Katie, who still works on the show, told us she loves it.

"I have never ever seen any of what is being reported," she said.

"I have never had an issue with any dancers or staff, I love them and they are very kind and respect me lots."

A beautician, Laura, who has been on the show for eight years, also said she had never seen any bullying.

She said she was "shocked" to hear some of the allegations, and that they made her "a bit apprehensive" about going back.

In July, Sherlock actress Abbington revealed she had first raised concerns with Strictly producers on her third day in rehearsals.

The BBC has said it takes issues "extremely seriously", while Abbington's dance partner Giovanni Pernice has denied "any claim of threatening or abusive behaviour".

But production staff we have spoken to have also flagged issues with raising complaints.

Oscar never complained about what was going on, because he said he felt he wouldn't be listened to.

"Unless you were a production executive or one of the producer’s friends, you weren’t empowered to raise issues," he said.

In response, BBC Studios told us it was "sorry" if Oscar didn't feel able to speak up about his experiences.

It said that using its initiative The Pledge on all its productions, including Strictly, "we proactively encourage everyone on set to raise concerns of inappropriate behaviour via several avenues, including anonymously to an external third-party whistleblowing service independent of the BBC/BBC Studios."

But other former runners, also speaking to us anonymously, have painted a similar picture.

Anika, who was a runner in the earlier runs of the show, joined the show to get work experience. She was initially excited to get the job, but she quickly found the work environment “exhausting”.

“There was a lot of shouting backstage,” she told BBC News.

She said one of the male dancers, who has since left the show, treated people "in an insane way. The way he spoke to women, including female dancers and junior staff, was disgusting and chauvinistic. We’d be warned about working with him".

She also said she didn’t feel she could raise issues.

“I was a nobody, a little runner, I didn’t think I could complain,” she said.

Anna, not her real name, was a runner on a Strictly Christmas special. She said members of the production team would “lose their tempers” at more junior staff.

She said often junior people didn't feel they could report things as they felt nervous of career repercussions.

Robert - also not his real name - worked on Strictly in the earlier runs of the show.

As a choreographer, he says he spent hours refining movements and perfecting routines. He says producers would get irate and shout at him if even the smallest thing went wrong, but he felt “afraid” to say anything back.

“I left of my own accord and wish there was something or someone I could have spoken to about my concerns.”

Strictly is a hugely prestigious show to work on, especially for those early on in their careers.

Over 35% of the team who have worked on the show for more than five years have been promoted. The show currently has series producers, series editors, senior producers, producer/directors, production managers and assistant producers who all started as runners and worked their way up.

But people we've spoken to have said that Strictly's dominant position in the entertainment world is actually part of the problem.

“There’s a sense that you’re lucky to be on the show as it is one of the biggest in the UK, so you should put up with all the problems you might face,” Robert told us.

That's something Jack, who worked on the show as a runner, also alleges.

He described an incident where a runner was asked to clean one of the dressing rooms. He says the producers told them they "should be lucky just to be on the show".

"I guess the problem is that [Strictly is] so big and so valuable to the BBC, one of their main money makers, those who are running the production feel untouchable," he said.

Jack said the vibe was "all about the glitz and glamour and no care for those making the show".

The whole experience made him want to leave TV for a while.

For the BBC, there's no doubt the whole saga has been damaging.

Last month, its director general Tim Davie apologised to Strictly contestants and warned that the show's professionals should not cross the line between being competitive and "unacceptable behaviour".

Following these latest allegations from production staff, BBC Studios said it "does not recognise" the claims, "nor will hundreds of production personnel who have worked with us through multiple series and across the two decades the show has been on air."

It added: "We act speedily when any issues are raised, and have thorough, effective, and longstanding processes to manage them - and we’re sorry if anyone didn’t feel able to talk about their experience on-set at the time.”

Some might argue that the stories coming to light are just part of the rough and tumble of TV.

But that's something people we've spoken to reject.

“I don’t think the rough and tumble of TV is a thing anymore. The world has moved on, it shouldn’t be happening," said Anika.

Mr Davie, for his part, has insisted the show will return as planned this autumn.

And this week, the BBC has started announcing the celebrity line-up for the 2024 series.

I asked Jane whether she thinks the show will survive.

"I think the BBC won't let it disappear," she said.

"But there needs to be change. It can't go on like this."