A Metropolitan police officer disciplined after an inquiry into misogynistic and racist messages has since been promoted, the Guardian has learned, as Cressida Dick was warned she could lose the confidence of the mayor of London. Misconduct was proven against the unnamed officer after a watchdog inquiry into messages about hitting and raping women, which were shared by up to 19 officers based mainly at Charing Cross police station. There were also messages about the deaths of black babies and the Holocaust, prompting accusations of a culture of misogyny and racism within the country’s biggest force. The officer was promoted from the rank of constable to sergeant despite being sanctioned for failing to report wrongdoing, the Met confirmed. The Independent Office for Police Conduct (IOPC) also revealed that three officers who remain in the Met sent potentially discriminatory messages. They were classed as being less serious than the messages that emerged on Tuesday. On Wednesday the London mayor, Sadiq Khan, put Dick on notice that she had to urgently reform the force or he could withdraw his confidence in her. The commissioner is appointed by the mayor and home secretary. For the first time sources made clear Khan would consider attempting to oust Dick if she fails to deliver rapid progress. The two had a 90-minute meeting described as “frank” after the revelations about Charing Cross and continuing crises gripping the Met. A source close to Khan said: “If the commissioner is not able to do so, then the mayor will have to consider whether she is the right person to lead the change needed at the Met.” The souring of relations came after the IOPC revealed shocking details of messages shared by Met officers between 2016, the year before Dick became commissioner, and 2018. They were uncovered by accident. One male officer wrote to a female officer: “I would happily rape you … if I was single I would happily chloroform you.” The IOPC said the behaviour was part of an offensive Met police culture, not just rogue individuals. “We believe these incidents are not isolated or simply the behaviour of a few ‘bad apples’.” The Met denies the force is plagued by misogyny and racism. Of 14 officers investigated, two deemed to be the worst offenders were sacked for gross misconduct. Misconduct was proven against another three, while another officer resigned before the disciplinary process was complete. On Wednesday the Met confirmed that one officer against whom misconduct was proven had been promoted. The force said the officer “attended a misconduct meeting and was given management action/advice about reporting wrongdoing”. A spokesperson said: “In order to achieve promotion, any officer has to go through a broad and rigorous assessment process. Following that they have to complete an extensive workbook to evidence their skills and abilities to ensure they are capable of the role/rank. “We have also spoken to line managers to confirm all those subject to the IOPC investigation who are still in the Met are performing to the expected standards … It was assessed that the police sergeant had breached the standards of professional behaviour by failing to challenge or report inappropriate behaviour.” The Met continued: “Because the police sergeant demonstrated that she had personally developed and learned since the incident, it was agreed by the IOPC that she should be subject to management action only, and that she should complete an attachment with a professional standards unit to develop her knowledge further.” The IOPC says that three officers investigated and who remain in the Met sent messages which “could be regarded as homophobic, racist or otherwise discriminatory”, adding: “The evidence we gathered indicated that three of those had sent messages of an inappropriate nature.” Dick’s five-year term expires in April and she then begins a two-year extension which Khan and the home secretary, Priti Patel, approved last year. Patel questioned the Met’s leadership during questioning by MPs on the home affairs select committee on Wednesday. She said there had been “too many instances where, in policing, we just see the most appalling behaviours” and added: “There are problems with the culture, and some aspects of the culture, within the Metropolitan police. “We are not seeing one-off incidences, this is not isolated. I also think it shows a failure of leadership in some quarters.” Patel said she had confidence in the commissioner but added: “There are lots of issues there where we need to see major … significant improvements: culture, delivery, accountability and protecting the streets.” A spokesperson for Khan said: “The mayor made clear to the commissioner how angry he is with a return to the bad days of the Met of his childhood in the 1970s and 80s, and that neither he nor Londoners will put up with this. “He has put the commissioner on notice. He said the Met needs to urgently show it has an effective plan for restoring the trust and confidence of Londoners in the police and to drive out the culture of racism, homophobia, bullying and misogyny which clearly still exists within its ranks.”