Boris Johnson is due to discover the outcome of a high court challenge over his decision to back Priti Patel after accusations of bullying. The FDA union brought a judicial review over the prime minister deciding last year to go against the findings of his then adviser on ministerial standards in order to back the home secretary. High court judges are expected to deliver their ruling in the case on Monday. Why was there a court case involving Priti Patel? The FDA union challenged a decision by Boris Johnson last year that Priti Patel did not breach the ministerial code by bullying her staff. This followed an investigation by the independent adviser on the code, Alex Allan, which concluded that she had bullied civil servants, including incidents of shouting and swearing at them. Allan concluded: “Her approach on occasions has amounted to behaviour that can be described as bullying in terms of the impact felt by individuals. To that extent her behaviour has been in breach of the ministerial code, even if unintentionally.” Despite this evidence, the prime minister sought to give weight to the home secretary’s assertion that any behaviour was unintentional and he therefore concluded that she had not breached the code. Allan left his role in Downing Street after Johnson contradicted his advice. What was Patel alleged to have done? Patel was accused of bullying staff across several government departments including the Home Office. Philip Rutnam, her former permanent secretary, said he was subjected to a “vicious and orchestrated campaign” against him in the media for challenging Patel’s alleged mistreatment of civil servants. According to reports, a senior Home Office official collapsed after a fractious meeting with Patel, who is understood to have successfully asked for another senior official in the department to be moved from their job. Further allegations emerged against Patel in the aftermath. An official in the Department for Work and Pensions (DWP) received a £25,000 payout after she alleged that Patel, who was employment minister at the time, had bullied her in 2015. The DWP did not admit liability and the case did not come before a tribunal. Officials in Patel’s private office at the former Department for International Development allegedly accused her of humiliating civil servants in front of others while a minister in 2017. Patel previously issued an “unreserved, fulsome apology” and said there were “no excuses” for what happened. What were the grounds for the challenge? The FDA union, which represents the UK’s most senior civil servants, claims that the prime minister’s decision was irrational given the obligations of the code, and his own words in its foreword that “there will be no bullying and no harassment”. The Home Office itself deals with this very issue in its definition of bullying: “Bullying is not about whether the perpetrator of the acts intended them or not, but about the impact on the recipient and how it makes them feel.” Solicitors for the FDA have also said that when Allan’s inquiry was announced in parliament by Michael Gove, the then minister for the Cabinet Office, Gove pledged his support for the home secretary. Days later, the prime minister, knowing he would be the final arbiter of that investigation, also pledged his full support at PMQs, the FDA claimed.