A decision by the parliamentary watchdog not to investigate the Conservative MP Chris Pincher over groping allegations has been appealed against, the Guardian understands. The scandal involving the then-deputy chief whip helped bring down Boris Johnson’s government in July, but alleged victims have waited months for news about the progress of their case. The Independent Complaints and Grievance Scheme – which vets claims about bullying, harassment and sexual misconduct – was said to have concluded it could not proceed with the investigation because the alleged incident took place outside parliament. At least one of the victims is understood to have lodged an appeal, which will be assessed by parliament’s standards commissioner, Kathryn Stone. Pincher is accused of groping several young men at a private members’ club, the Carlton Club, about a mile from the House of Commons, in late June. He admitted in the aftermath of the allegations that he had drunk too much, and has stayed away from parliament since. However, the row took on greater significance when Downing Street was found to have issued untrue statements claiming Johnson had not been aware of specific allegations about Pincher before promoting him to the whips’ office in February. In an unprecedented move, a former permanent secretary at the Foreign Office went public to say that when Pincher was a minister there, a groping complaint was made against him and upheld, with the prime minister informed directly. Following Partygate and questions about Johnson’s conduct and integrity, it was the final straw that led Tory MPs to call a no-confidence vote. No 10 also initially resisted removing the whip from Pincher in a move that further compounded anger in the party, given several MPs witnessed the alleged incident in the Carlton Club. Pincher has remained silent for months and no longer publishes a monthly column for The Critic magazine “on drink”. In a statement released in July, he said he would “cooperate fully” with inquiries into his behaviour, adding he was seeking “professional medical” help and was “truly sorry”. Parliament’s two standards watchdogs were criticised earlier this month for stopping work during the 10-day mourning period after the Queen’s death. A Commons spokesperson said they “cannot confirm or deny any investigations” as the ICGS “operates on the basis of confidentiality for the benefit of all parties”. They added: “We cannot provide any information on complaints or investigations, including whether a complaint has been received or an investigation is ongoing.”