TV presenter Gregg Wallace will step down from his role on MasterChef after the BBC received complaints about alleged misconduct.

Presenter Kirsty Wark, who took part in Celebrity MasterChef in 2011, has claimed Wallace told “sexualised” jokes during filming. Wallace is accused of inappropriate sexual comments by 13 people who worked with him on various shows over a 17-year period, according to a BBC News investigation.

Wark, a former Newsnight presenter, told BBC News that on two occasions during early morning filming, Wallace told stories and jokes of a “sexualised nature” to contestants and crew. She said she felt strongly that the comments were “really, really misplaced.”

“There were two occasions in particular where he used sexualised language in front of a number of people and it wasn’t as if anyone had engaged in it,” she said. “It was completely one-way traffic. But I think that made people uncomfortable and something I really didn’t expect.”

Other people told the station that Wallace spoke openly about his sex life, once taking off his top in front of a female worker and saying he wanted to “give her a fashion show,” and telling a younger colleague that he didn’t wear boxer shorts under his jeans.

BBC News said it began investigating Wallace in the summer after becoming aware of the allegations and hearing claims relating to five shows from 2005 to 2022.

Wallace’s lawyers said the claim that Wallace, who has co-hosted the popular BBC One cooking show with John Torode since 2005, engaged in sexually harassing behavior was completely false.

Rod Stewart, whose wife Penny Lancaster appeared on Celebrity MasterChef in 2021, took to his Instagram account later on Thursday to comment on Wallace’s break from the show. Stewart called him a “chubby, bald-headed, ill-mannered tyrant” and said Wallace humiliated his wife.

He wrote: “So Greg (sic) Wallace is fired from Master Chef. Good thing you’re over, Wallace… You humiliated my wife when she was on the show, but you left that out, didn’t you? You are a chubby, bald, ill-mannered bully. Karma got you. Sir Rod Stewart.”

MasterChef’s production company, Banijay UK, said it had launched an investigation after the BBC received complaints about Wallace’s behavior and said the 60-year-old was “committed to cooperating fully throughout the process”.

The statement said: “While this review is ongoing, Gregg Wallace will be stepping down from his role at MasterChef and is committed to cooperating fully throughout the process.” Banijay UK’s duty of care to employees is always paramount and our behavioral expectations are made clear to both cast and crew on all productions, with numerous opportunities on set to raise concerns, including anonymously, and make this clear.”

The company said the allegations had not been raised directly with it but that it believed “it is appropriate to conduct an immediate external review to conduct a full and impartial investigation.” It said anyone with issues or concerns could confidently contact [email protected].

A BBC spokesman said: “We are always clear that any behavior that falls below the standards expected by the BBC will not be tolerated.” If a person is commissioned directly by an external production company, we will forward any complaints or complaints Concerns will be passed on to this company and we will always support them as we address them.”

BBC News also said Wallace had been warned by the BBC following a complaint in 2018 and further incidents had been alleged. In October, Wallace denied claims that he had bragged about his sex life to a younger BBC employee, took off his top in front of her and said he would never “flirt” or “hit on” another woman.

He said on Instagram at the time that the allegation was immediately investigated when it happened by the BBC six years ago. He said: “And the result was that I hadn’t said anything sexual. I have to repeat this again. I didn’t say anything sexual. Contrary to what the newspapers say, six years ago no one accused me of flirting or hitting on anyone.”

It is understood a pre-taped broadcast of MasterChef: The Professionals featuring Wallace will air as planned on Thursday and the series will continue into December.

The BBC launched an independent review of its working culture in October after a series of damaging scandals at the broadcaster led to questions being raised about how it prevents abuse by and among its staff.