The BBC’s director general has apologised to Strictly Come Dancing contestants who have had negative experiences on the show.

Tim Davie said he was “disappointed” to hear that several celebrity contestants had complained about abusive behaviour by their dance partners in rehearsals.

The BBC One show’s professionals should not cross the line between being competitive and “unacceptable behaviour”, he warned.

“There will be a degree of competitiveness and will to do well, but there are limits and the line should never be crossed. We never tolerate unacceptable behaviour of any kind.”

Strictly professionals Graziano Di Prima and Giovanni Pernice have both left the show after allegations about their behaviour in training.

Pernice has denied “any accusations of abusive or threatening behaviour”.

Di Prima’s spokesman has admitted the dancer kicked partner Zara McDermott in rehearsal. He has said he deeply regrets “the events that led to my departure from Strictly”, and that his “intense passion and determination to win might have affected my training regime”.

Speaking to journalists on Tuesday, Mr Davie said he was “very sorry that anyone has had an experience that hasn’t been wholly positive that’s something we do need to reflect on and I’m sorry about that”.

“There are clearly learnings specifically about oversight in the training rooms that we had needed to address,” he added.

With the “benefit of hindsight, you think could we have done more?” he added.

He also confirmed the show will return this autumn, despite its problems.

Last week, the BBC announced it will put a member of Strictly production staff in all rehearsals in the future to observe behaviour.

There will also be enhanced training and two new dedicated welfare producers – one for the celebrity contestants and the other for the professional dancers.

Launching the BBC’s annual report, the director general described Strictly as a “wonderful show that brings a lot of joy to a lot of people for 20 years”.

“To those involved and millions at home, hundreds of people – be they pros, contestants or crew – have had a brilliant experience.

“At the same time, if someone feels something is wrong and they want to talk, we want them to raise it of course and be in no doubt that we will take it seriously and deal with it appropriately.

“I won’t talk about individuals, but anyone who wants to talk to us I hope feels that they can.”

Mr Davie added: “It’s vital we have the right protocols and structures and we keep these under review and confirmed changes last week. It is essential these are right for everyone.”

This year’s celebrity participants are expected to be revealed in August.

“We have a brilliant line-up this year and are keen to get going,” he said.

More on Strictly Come Dancing:

• A timeline of how the Strictly saga has unfolded
• Strictly left Paralympian with injuries he’ll ‘never get over’
• Giovanni insists ‘I’ll be back’ after Strictly accusation
• Abbington accuses Pernice of ‘cruel and mean’ behaviour
• ‘Frustrating’ and ‘pressurised’: Life inside Strictly rehearsals
• Strictly to give stars chaperones after complaints
• Zara speaks about ‘distressing’ Strictly incidents