Boris Johnson has been accused of double standards after writing to ministers and senior civil servants claiming there is “no place for bullying” in the wake of a damning investigation into the home secretary, Priti Patel. The prime minister and the cabinet secretary, Simon Case, wrote a joint email on Monday calling for relationships of “mutual trust and respect between politicians and their officials”. On Friday, Johnson broke with precedent and refused to sack Patel after an inquiry concluded she had broken the ministerial code following bullying allegations across three government departments. Sir Alex Allan, the prime minister’s adviser on ministerial standards, quit his post after Johnson contradicted his report by vigorously defending the home secretary and keeping her in her role. Dave Penman, the head of the FDA union that represents senior civil servants, said the prime minister’s latest words would do little to reassure public servants. “In August 2019 he set out, in precise terms in the foreword to the ministerial code, that ‘there must be no bullying and no harassment’,” Penman said. “In the first test of his commitment to these words, he has transparently chosen partisan political interest over the interests of the victims of the home secretary’s behaviour as well as the broader standards that should rightly be expected of ministers. “If the prime minister was serious about his commitment to these standards, he would introduce an independent and transparent process for dealing with these complaints, that was free from the political interference he has so blatantly shown in regard to the home secretary.” In a written ministerial statement, which acknowledged that Allan had concluded that Patel’s behaviour could “on occasion” be described “as bullying in terms of the impact felt by individuals”, Johnson said: “Together with the cabinet secretary, I have this morning written to all ministers and permanent secretaries. This letter sets out the paramount importance of relationships of mutual trust and respect between politicians and their officials. “This includes keeping internal conversations private, feeling able to speak freely and honestly about matters of state and to speak constructively about things that are not working so that we can fix them together promptly. “I am clear that there is a particular duty on ministers and permanent secretaries to create jointly across government a culture which is professional, respectful, focused and ambitious for change and in which there is no place for bullying. The cabinet secretary and I are enormously grateful to civil servants for the commitment they have shown as we navigate through these challenging times.” Johnson added that he had “full confidence” in Patel and that he considered “this matter now closed”. In a published summary of the long-delayed report, Allan said Patel’s conduct had “amounted to behaviour that can be described as bullying”, and highlighted instances of shouting and swearing. He concluded she had breached the ministerial code, even if unintentionally. One of the justifications Johnson used for defending Patel was the element of Allan’s report that said she had been unaware of the impact of her behaviour because no Home Office official had complained about her. Sources have said, however, that Allan sought to interview the former top Home Office civil servant Sir Philip Rutnam, who resigned after clashing with Patel, but government officials blocked him. Offering what she described as an “unreserved, fulsome apology”, Patel has seized on Allan’s finding that she had received no feedback on the impact of her behaviour. Rutnam, who is suing Patel for wrongful dismissal under whistleblowing laws, issued a statement on Friday that said she was advised not to shout and swear at staff the month after her appointment in 2019, and that he had told her to treat staff with respect “on further occasions”.