Rishi Sunak has defended his deputy prime minister and justice secretary, Dominic Raab, saying he does not recognise claims from multiple civil servants that he bullied staff. Sunak gave a robust defence of Raab, having already been criticised over his judgment after promoting other controversial ministers including Suella Braverman and Gavin Williamson. “I don’t recognise that characterisation of Dominic and I’m not aware of any formal complaints about him,” he told reporters onboard his plane en route to the G20 summit in Bali. “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.” However, Simon McDonald, the former permanent secretary at the Foreign Office when Raab was in charge there, has suggested that bullying claims were accurate. He described Raab as “one of the most driven people” he had ever worked for and a “tough boss”, before admitting his comments may be “euphemisms”. Asked by the LBC radio presenter Andrew Marr whether the characterisation of Raab as “somebody who could bully, and around whom bullying happened” was plausible, he replied: “Yes.” Sunak was speaking as ITV reported a new claim that eight people working in Raab’s private office when he was foreign secretary claimed to have been bullied or harassed at work. The results of an HR survey leaked to the broadcaster found that 15 people in the office witnessed seeing someone else being bullied or treated unfairly. The person or persons doing the bullying were not identified in the survey. The prime minister suggested that could not be considered proof of poor behaviour by Raab. “My understanding is that these surveys are annual and relate to the overall work environment, not to individuals,” he said. It follows the Guardian’s report that Raab’s return to the Ministry of Justice prompted officials to be offered the opportunity to move from his private office because of concerns about his behaviour. They were offered “respite or a route out” of the department and at least 15 staff were given reassurances as a result of their anxiety. The department’s permanent secretary, Antonia Romeo, is said to have “read him the riot act” upon his return to the MoJ after Sunak became prime minister – warning Raab about treatment of staff. Raab was one of Sunak’s most high-profile and early supporters in the leadership contest, taking on difficult broadcast rounds in his defence and acting as a key attack dog against Liz Truss. His actions in the leadership campaign led to him being sacked from the cabinet by Truss but he was restored to his previous post at the MoJ by Sunak. No 10 said the prime minister had full confidence in Raab and denied he was aware of any formal complaints against his deputy. However, pressed repeatedly on the matter, the spokesperson failed to deny that an informal complaint may have been made. Over the weekend, the Observer revealed that concerns were raised about Raab’s treatment of officials during his time as Brexit secretary in 2018. A senior source said there was a “serious expression of concern” to the Cabinet Office by a key official in the department, accusing Raab of “unprofessional, even bullying” conduct towards staff in his private office. No action was taken. The No 10 spokesperson added: “As the prime minister has said before, people in public life should treat others with consideration and respect. Those are principles that this government will stand by. “There are established procedures by which civil servants can raise complaints. These processes allow allegations to be looked and considered with due process and a fair hearing. We are not aware of any formal complaint having been raised.” The claims about Raab follow the resignation of the Cabinet Office minister, Gavin Williamson, another prominent Sunak ally during the leadership campaign. Williamson was accused of bullying MPs and officials, including sending expletive-laden texts to the former chief whip Wendy Morton, and civil servants said he had used threatening language. Williamson has denied allegations of bullying. Sunak did not issue as vigorous a defence of Williamson after the texts to Morton came to light and said there would be an investigation after condemning the language used. Williamson resigned later that week as minister in the Cabinet Office after a slew of damaging stories about his time as defence secretary and chief whip. A spokesperson for Raab said: “Dominic has never received nor been made aware of any formal complaint against him. He consistently holds himself to the highest standards of professionalism and enjoys good working relationships across Whitehall.”