Rishi Sunak is standing by Deputy Prime Minister Dominic Raab as further allegations about his conduct emerged.
Mr Raab was reportedly warned about his behaviour towards officials while he was foreign secretary.
The concerns were raised with Mr Raab by Lord McDonald, who was the senior civil servant at the Foreign Office, and the mandarin also informally discussed the situation with the Cabinet Office’s propriety and ethics team, the Guardian reported.
In a radio interview earlier on Monday, Lord McDonald had acknowledged that allegations Mr Raab could be a bully were plausible.
Mr Raab, who will stand if for Mr Sunak at Prime Minister’s Questions on Wednesday, was already in the spotlight over claims about clashes with officials at the Ministry of Justice – staff were reportedly offered a “route out” of his department when he was reinstated in October.
But the Prime Minister told reporters travelling with him to Indonesia for the G20 summit: “I don’t recognise that characterisation of Dominic and I’m not aware of any formal complaints about him.
“Of course there are established procedures for civil servants if they want to bring to light any issues.
“I’m not aware of any formal complaint about Dominic.”
Lord McDonald, who was the permanent secretary at the Foreign Office while Mr Raab was there, said bullying allegations were believable.
Asked by LBC radio if characterisation of Mr Raab as someone who could bully and around whom bullying could happen, he replied: “Yes.”
Lord McDonald added: “Dominic Raab is one of the most driven people I ever worked for, he was a tough boss.
“Maybe they are euphemisms, but I worked closely with him and I didn’t see everything that happened.”
According to the Guardian’s sources, Lord McDonald spoke to Mr Raab on several occasions about how he treated staff in his private office and during meetings – although none made an official complaint.
Lord McDonald, now a crossbench peer, was said to have had several informal conversations with the head of the propriety and ethics team (PET) at the Cabinet Office between 2019 and 2020 about the issue.
A spokesman for Mr Raab told the Guardian: “Dominic had frequent discussions with his permanent secretary at the Foreign Office about how best to run the department and ensure that it delivered to the highest standard in challenging circumstances such as during Covid.”
A survey of 20 people working in Mr Raab’s private office when he was foreign secretary in 2019 showed that 40% reported personal experience of bullying and harassment – though not necessarily by Mr Raab – and 75% witnessed it, ITV reported on Sunday.
Asked about the leaked results, Mr Sunak said: “My understanding is that these surveys are annual and relate to the overall work environment, not to individuals.”
Sir Philip Barton, the current senior civil servant in the Foreign Office, told MPs he would not “comment on what appears to have been a leak of a document”, but “for any scores in any area you need to look under the bonnet and look at what lies behind them rather than inferring any particular thing in any particular direction”.
The mandarin, who succeeded Lord McDonald in 2020, said: “I have worked very closely with successive foreign secretaries to build a culture of respect and kindness across the whole of the department.”
The head of the FDA union, which represents senior civil servants, called on Mr Sunak to appoint a new independent adviser on ministers’ interests – the post has been vacant since Lord Geidt quit in June – and reform the complaints system to help address a “toxic work culture” in Whitehall.
In a letter to the Prime Minister, FDA general secretary Dave Penman said: “As we have seen over the last few weeks, there is increasing scrutiny over the conduct of minister and, in particular, accusations of bullying – behaviour that has no place in a modern workplace.”
An independent investigation into Dominic Raab's conduct is now urgently required. The PM himself must come clean on what he knew when he appointed him.
It's anti-bullying week, but instead of holding the bullies to account, Rishi Sunak is cowering behind them.#AntiBullyingWeek
— Angela Rayner 🌹 (@AngelaRayner) November 14, 2022
Deputy Labour leader Angela Rayner demanded an independent investigation into Mr Raab.
“Rishi Sunak clearly knew about Dominic Raab’s reputation when he reappointed him to his Cabinet,” she said.
Meanwhile, the Liberal Democrats have written to Cabinet Secretary Simon Case to ask for a list to be published of ministers with “credible allegations of bullying” made against them.
The Prime Minister was already under pressure for appointing Sir Gavin Williamson to his senior team despite being told he was under investigation for allegedly bullying a colleague, claims that caused Sir Gavin to quit.
He also faced criticism for reinstating Suella Braverman as Home Secretary just six days after she was forced to step down over a security breach.