Dominic Raab has insisted he “behaved professionally at all times” despite facing an official inquiry into his conduct.

The deputy prime minister is being investigated by senior lawyer Adam Tolley KC over numerous bullying allegations.

But, denying the allegations, Mr Raab told The Telegraph newspaper he is “confident” he has behaved appropriately.

“I’m confident I have behaved professionally at all times. And I will engage with the inquiry, and of course I would not want to say anything that prejudiced it,” he said.

Asked if he was any more robust than former prime minister Margaret Thatcher, he said: “I think it’s difficult to compare different eras.

“But I think standards of professionalism, whether they’re in the business sector, the voluntary sector or the public sector, should involve setting high standards and zero bullying, and those two things are perfectly reconcilable.”

In a separate interview with the BBC, Mr Raab said he would not comment on recent “anonymous reports in the media”.

He added that, in his experience, such reports were “mostly incorrect”.

Prime Minister Rishi Sunak has resisted calls for Mr Raab to be suspended or to step aside while he is investigated, saying he will wait until the conclusion of the inquiry first.

“The independent adviser is conducting his investigation; I can’t prejudge the outcome of that investigation. It’s right that it concludes,” the PM said earlier this week.

“But as people have seen from how I’ve acted in the past, when I’m presented with conclusive independent findings that someone in my government has not acted with the integrity or standards that I would expect of them, I won’t hesitate to take swift and decisive action.

“That’s what I’ve done in the past. But with regard to this situation, it’s right that we let the independent process continue.”

Dave Penman, the leader of the FDA union, which represents senior civil servants, said Mr Raab should stop giving public statements about the inquiry into bullying allegations against him.

“What we need is for this inquiry to conclude as quickly as possible and for the protagonist in it, who has been reminded about confidentiality, to stop giving comments to the public,” he told BBC Radio 4’s Today programme.

“This demonstrates ably the issue of why the prime minister should have suspended Dominic Raab because, while these allegations are hanging over him, he is still serving as a minister, there are still concerns about someone who conducts themselves potentially in that way still being in charge of civil servants.”

Read more: The five days of allegations against the deputy PM

Meanwhile, questions are also swirling about what Mr Sunak knew of the allegations after a source told Sky News the PM was told about Mr Raab’s “unacceptable behaviour” over the summer before he became prime minister and appointed the deputy PM to his cabinet role.

The source told Sky News’ political editor Beth Rigby that Mr Sunak was made aware of Mr Raab’s conduct but the PM was never “directly told” about specific issues.

Downing Street has said Number 10 officials never advised the PM against appointing Mr Raab and that he was “not aware of any formal complaints” at the time of appointing him.

No 10 has insisted it is right to wait for the investigation to be concluded before taking any action.

It has not put a timeframe on when the investigation will finish, only saying it is hoped it will be concluded “swiftly”.