Theresa May has been accused of breaking the code for public appointments as prime minister after it emerged that she blocked the appointment of a drugs expert to the Home Office’s drug advisory panel because he had been critical of the scale of NHS cuts. The individual, who does not wish to be named, was barred from the Advisory Council of Misuse of Drugs (ACMD) after he co-signed a letter claiming that the former health secretary Jeremy Hunt was “gaslighting” public health workers. He becomes the third respected expert to have been blocked from the panel after having their online activity vetted by government officials since 2017. There has been growing concern over political interference in the appointment of experts to supposedly independent committees. In October 2018 the then home secretary, Amber Rudd, had been content to appoint the expert, but May overruled her. May was previously accused of attempting to delete sentences from a Whitehall report that concluded there was no link between harsh drug laws and levels of illegal substance use. The expert’s case came to light when the commissioner for public appointments, Peter Riddell, on Monday published a ruling on the matter, after the expert had complained that his comments online had been misrepresented by officials who compiled a dossier of his posts. Concerns were raised about comments on a teachers’ strike over funding at the school of the expert’s son, a critical letter about drug treatment cuts sent to a periodical in response to a book review, and the signing – alongside hundreds of other clinicians – of an open letter to Hunt about cuts to mental health services that alleged he was “gaslighting” clinicians over NHS funding levels. The decision by No 10 led to the post being vacant for months. Previously, a chief pharmacist at an addiction service and the director of drug law centre were blocked from the ACMD by the Home Office after the former criticised NHS cuts and the latter called for drug policy reform. This prompted a criminal justice expert to quit, claiming political interference in the appointment process was seriously undermining the panel’s independence. Prof Alex Stevens, expert who quit, said: “This case shows clearly that ministers have broken the Nolan principles of public life and the governance code for public appointments. Both require ministers to act solely in the public interest when making public appointments. “By barring this and other candidates from appointment to the ACMD on the basis of their prior criticisms of government policy, they have damaged the independence of the ACMD and breached their duties to act objectively and impartially.” Graham Parsons, the pharmacist also blocked from the ACMD, tweeted: “Lesson is don’t criticise the government in any form or you won’t get on an independent body even if you are an expert in the field and have evidence-based practice as the foundation for your practice.” Stevens highlighted concerns that there was no official barrier to ministers filling “purportedly independent advisory committees with people whose views they find ‘suitable’,” after the Office of the Public Commissioner said it had “no remit to rule on” blocked appointments or “the relevance and proportionality” of vetting. Riddell ruled that the expert was treated fairly at interview but should have been given an opportunity to respond to the concerns raised following vetting, along with being offered feedback. In response to criticism on social media, the commissioner tweeted: “You raise important points about the independence of ACMD but the government’s code allows ministers to decide public appointments without giving reasons. As PAC [public appointments commissioner], I regulate the fairness of the process but this doesn’t involve questioning ministerial motives.” A Home Office spokesperson said: “Ministers make appointments to the ACMD in line with the governance code for public appointments. The commissioner for public appointments has found that the Home Office followed the process correctly in recruiting members to the ACMD.”