Production staff who formerly worked on Strictly Come Dancing have complained of a toxic work culture and accused the BBC of failing to take their complaints seriously, in a fresh blow to the corporation’s primetime show, the Observer can reveal.

One former staff member alleged they had been subjected to sexist and sexualised comments, including intrusive questions about their sex life, while another claimed they witnessed “talented co-workers treated with cruelty”.

The complaints from the workers cover several series and go back as far as 2016. A third staff member, who worked on the show eight years ago, claimed that the workplace culture they experienced was “tense, toxic, uncomfortable”.

A spokesperson for BBC Studios said: “The welfare of our crews working on each series of Strictly is always of paramount importance to us. We act speedily when any concerns are raised, and we have thorough, effective and longstanding processes to manage them.” They added: “We do not recognise the claims relating to a negative workplace culture.”

In recent weeks Strictly Come Dancing has become the subject of intense scrutiny after allegations about misconduct behind the scenes from a number of its professional dancers. Giovanni Pernice and Graziano Di Prima have left the show after facing allegations about their conduct behind the scenes.

Pernice strongly denied allegations of “threatening and abusive behaviour”. Di Prima, via his spokesperson, admitted to kicking his celebrity partner Zara McDermott during a rehearsal and said that he “deeply regrets” events that led to his departure. His spokesperson added that it was “absolute rubbish” that a single incident was typical of what went on during “weeks and weeks of training”.

Video footage has also emerged from past series showing other professional dancers shouting at their female dance partners.

The Rev Richard Coles, who took part in the show in 2017, said a veteran Strictly staff member told him the dancing contest is “a wonderful show with a dark heart”.

The BBC’s director general, Tim Davie, last week praised Strictly as “a wonderful show that brings a lot of joy to a lot of people and has done so for 20 years”.

But he added: “At the same time, if someone feels there was something wrong or they would talk about their experience, then of course you want them to raise that with us. And be in no doubt we’ll take it seriously, listen and deal with it as appropriate.”

Until now, the focus has been on the dancers and their celebrity partners. But the Observer has spoken to several former production staff members who have raised a series of concerns about the way they and some of their colleagues were treated, suggesting the issues went beyond the rehearsals and behaviour of professional dancers.

A former member of staff, who wished to remain anonymous, said they had experienced inappropriate comments on set in 2022 from another, more senior member of staff. They allege they were subjected to sexist and sexualised comments, including intrusive questions about their sex life which made them feel “uncomfortable” and explicit sexual comments about the female dancers. They claimed that the behaviour “crossed a line”. The Observer has seen contemporaneous WhatsApp messages that corroborate their account.

When they checked the procedure for raising a complaint, the staff said they were told to raise their concerns with the Film and TV Charity, which supports behind-the-scenes workers.

“It was incredibly frustrating,” said the former staff member. “It left me at a dead end. It felt a bit blasé – handing off the responsibility to a charity rather than the company that is actually employing all of these people.”

A document from 2022 seen by the Observer shows that while BBC staff and fixed-term contract employees were directed to an external whistleblowing hotline if they had concerns about the workplace environment, those on freelance contracts were directed to “support through our partners at the Film and TV Charity, including whistleblowing services”.

The charity, however, said: “The charity is not for whistleblowing.”

BBC Studios said: “There is one whistleblowing service across the BBC Group which is independent and run by a third party that’s accessible to everyone – staff and freelance colleagues alike. Everyone is given the details of the Film and TV Charity support line, not for whistleblowing, but for the purposes of additional resource and support.”

A member of the production team, who also wished to remain anonymous, claimed that the workplace culture they experienced on the show in 2016 was “tense, toxic, uncomfortable”. They added: “The disparity between what you see on screen and what happens behind the scenes is enormous.”

A third source, who worked on multiple series of the show, highlighted issues with the leadership of the programme. “In recent years we’ve seen talented co-workers treated with cruelty, incompetence rewarded, and egos unchecked. Total compliance is demanded of some, absolute free rein given to others,” they said.

“It is heartbreaking to see the show tarnished. The majority of people who work on the team have put many years of heart and soul into their work, but sadly the current senior team have let us all down badly.”

In a statement, BBC Studios said: “The welfare of our crews working on each series of Strictly is always of paramount importance to us. We act speedily when any concerns are raised, and we have thorough, effective, and longstanding processes to manage them.

“The show is a fast-paced live TV production environment that has attracted hundreds of people in the industry to work on who have had a positive experience, so we do not recognise the claims relating to a negative workplace culture – or that there are flaws in our whistleblowing process.

“In 2022, we announced the introduction of our industry-leading initiative The Pledge on all our productions, including Strictly, which proactively encourages anyone on our sets to raise concerns of inappropriate behaviour via a number of avenues, including anonymously to Navex Global, an external whistleblowing service independent of the BBC and BBC Studios.”