Senior Ministry of Justice officials could quit if Dominic Raab is cleared of bullying, the Guardian understands, with the fate of the deputy prime minister to be decided as soon as Thursday. Preparations at the heart of government are ramping up for the publication of the long-expected report on claims of bullying by Raab. A Whitehall source said the findings by Adam Tolley KC could be passed to the prime minister, Rishi Sunak, as soon as Thursday. Officials in the Cabinet Office’s propriety and ethics team are also said to be braced for the potentially bombshell dossier to land imminently. The justice secretary has faced multiple formal complaints over his dealings with civil servants including claims, first revealed by the Guardian, that he bullied and belittled staff, driving some to tears or causing them to throw up before meetings. The inquiry has heard from more than two dozen complainants. Raab, 49, who is also deputy prime minister, has consistently denied any bullying of civil servants, including some in senior roles. One official told the Guardian: “If he stays in the department, senior people will want to walk.” Another said that several senior colleagues would start looking for new jobs and “leave in the near future” but stop short of quitting on the spot. MoJ officials believe that it is likely, given the breadth of the evidence, that Sunak will have to sanction Raab – warning that if he does not, it would be “so demoralising” for staff. Internal briefings have been prepared about how to handle the moment when the report – nearly five months in the making – finally drops, the Guardian understands. Sir Jake Berry, the former Conservative party chair, criticised the “outdated” system for dealing with such complaints in Westminster during an appearance on ITV’s Peston show on Wednesday night. “It does seem to me quite wrong that when people are under these kinds of investigations of this type that they continue in their job,” Berry said. “Whatever the outcome is, and we’re going to find out [on Thursday], I actually think there’s a fundamental rethink required about how we deal with these sorts of allegations. “It’s a massively outdated system that isn’t what our constituents would expect of any of us.” Raab is not believed to have any public engagements on Thursday, and Sunak was flying back from Belfast on Wednesday night after hosting a gala dinner. Sunak was expected to receive the report and make a decision on the justice secretary’s future within hours. The report will then be made public alongside his decision. The prime minister is also likely to face questions in the report’s aftermath about what he knew and when. Insiders have said senior civil servants warned him of “issues” about Raab’s behaviour before he appointed him as his deputy. Senior Tories believe that the report and a decision about Raab’s future as deputy prime minister should be made as much in advance of the 4 May local elections as possible. However, the timing of when the report is finished is ultimately in the hands of Tolley. A person with knowledge of the investigation said Tolley had interviewed Raab multiple times and done a “thorough job”. They believed he had weighted the evidence he had received according to the proof provided by witnesses. “It’ll be shades of grey,” they said. “A presentation of statements of fact means that whether the behaviour amounts to bullying is in the eye of the beholder. In the end, it will be the PM’s call.” Among those who have been interviewed or given written evidence to the inquiry are three Whitehall permanent secretaries: Antonia Romeo, the permanent secretary at the Ministry of Justice; Simon McDonald, a former permanent undersecretary at the Foreign Office; and Philip Rycroft, a former permanent secretary at the now-disbanded Department for Exiting the European Union. McDonald is understood to have spoken to Raab on several occasions during his tenure about how he treated staff in his private office and during meetings. It was revealed on Wednesday that Raab has paid for his own legal team to defend him against the allegations, according to an entry in the register of ministerial interests. No 10 said Raab had not been entitled to taxpayer-funded legal support, unlike former prime minister Boris Johnson, who has had his legal advice paid for by approximately £222,000 of public funds in order to prepare for a privileges committee investigation. Sunak’s spokesperson said it was an “established process” and suggested that Johnson’s entitlement to public funds was because it was in relation to government business – in his case misleading parliament – rather than specific personal behaviour. Raab’s entry in the register reads: “The minister has engaged lawyers at his own expense in relation to the investigation being conducted by Adam Tolley KC.” The report’s publication is likely to be the first of two difficult inquiries published in the coming days, with the release of the independent report on the conduct of the BBC chair, Richard Sharp, also expected in the middle of next week. A source close to that inquiry said it was expected to be a “very uncomfortable” report on how he was recommended for the job by Johnson. Adam Heppinstall KC, who was commissioned to undertake the inquiry, has finished his report. It is expected to be critical of how Sharp failed to reveal while applying for the job that he had helped an acquaintance arrange a secret £800,000 personal loan facility for Johnson, who was struggling with money issues.