Rishi Sunak has urged officials who may have concerns about Dominic Raab’s behaviour to “come forward” and make a complaint after a top civil servant said Raab was so “demeaning and abrasive” to junior colleagues that many were “scared” to enter his office. Speaking to broadcasters at the G20 summit in Bali, the prime minister continued to stand by his deputy, saying he “did not recognise” the characterisation of Raab as a bully but said civil servants should “avail themselves” of the formal complaints process if necessary. He told the BBC: “I was not and I’m not aware of any formal complaints about Dominic’s behaviour. But I would say if people do have concerns, whether it’s about any individual, that they should come forward and talk to people about those.” The Guardian understands that top officials at the Ministry of Justice, Raab’s current department, have now ruled that there should always be a senior civil servant in the room in meetings with him due to the recent allegations. Sunak continued to refuse to answer questions about whether he had been informed of any informal complaints about the justice secretary’s alleged bullying across three government departments including the MoJ, the Brexit department and the Foreign Office before he reappointed him to his cabinet. When asked in a separate interview with ITV News whether there should be an investigation into Raab’s behaviour given the number of allegations reported, Sunak indicated this could not happen unless witnesses came forward. “There are established processes in place for people to raise concerns. In all workplaces – private, public – if people have concerns they should raise them, because unless people raise them it’s hard for people to actually then look into them and make any changes that are necessary, so I would urge people to do that. Those processes are confidential and it’s right that they are used.” The Guardian has reported that the former permanent secretary of the Foreign Office Simon McDonald warned Raab about the way he treated officials in his private office and then reported his concerns to the propriety and ethics team at the Cabinet Office. Now a crossbench peer, McDonald has confirmed the report, telling Times Radio: “It was language, it was tone, he would be very curt with people. He did this in front of a lot of other people. I think people felt demeaned. I tried to have that conversation with him.” He also confirmed he had spoken informally to the Cabinet Office. McDonald said Raab, who has denied the allegations, was not aware of the impact his behaviour was having on people. “When I worked for him, Dominic Raab was not aware of the impact of his behaviour on the people working for him, and couldn’t be made to see that impact. Colleagues did not complain to me formally. It was kind of their professional pride to cope,” he said. “But many were scared to go into his office. His sort of defence was that he treated everyone in the building in the same way. He was as abrasive and controlling with junior ministers and senior officials as he was with his private secretaries.” McDonald said he hoped Sunak would reform the system for dealing with allegations of bullying. “What we have at the moment is not fit for purpose. Action is only taken if there is a formal complaint and there is a feeling in the system that the system is stacked in favour of the minister or senior official. So people hesitate to make a formal complaint because of the effect on themselves.” Dave Penman, the head of the FDA union representing senior civil servants, called on Sunak to reform the complaints system to help address a “toxic work culture” in Whitehall. In a letter, Penman urged the prime minister to appoint a new independent ethics adviser. The post has been vacant for five months since Christopher Geidt quit in June amid concerns over Boris Johnson’s role in the Partygate scandal. Downing Street said the recruitment process was continuing “at pace”. The Guardian has also reported that a senior official at the Department for Exiting the European Union handed a document to the Cabinet Office about alleged bullying of staff by Raab when he was Brexit secretary. It is understood that Philip Rycroft, the former permanent secretary to the department, shared general concerns about Raab’s behaviour with the then cabinet secretary, Mark Sedwill, after they were raised with him by private office staff. Other reports suggest that Sedwill’s successor, Simon Case, was aware of Raab’s alleged behaviour at the MoJ. A spokesperson for Raab said: “The deputy prime minister has worked in government for over seven years as a minister or secretary of state across four departments and enjoyed strong working relationships with officials across Whitehall. He consistently holds himself to the highest standards of professionalism and has never received nor been made aware of any formal complaint against him.”