A former MP has been cleared of sexual harassment alleged to have taken place several years ago in a House of Commons bar, in the first ruling by a new body set up to investigate potential misbehaviour by parliamentarians. The claim against Ross Thomson, the Conservative MP for Aberdeen South from 2017 to 2019, was investigated and dismissed in an initial investigation, and a follow-up investigation by the commissioner for standards last year. But the complainant appealed and had their case examined by an independent expert panel – the first time such a group has been formed to consider a case. The system was set up to avoid MPs being involved in judging the actions of their colleagues and as a result avoiding the appearance they may have acted more or less favourably towards them. The allegation against Thomson came from another former Scottish MP, Labour’s Paul Sweeney, who said Thomson had first touched and stroked him for several minutes, then groped his backside and genitals on 30 October 2018. An initial investigation upheld the first claim but dismissed the second – and concluded Sweeney made it “maliciously”. The commissioner for standards upheld there was no breach of the sexual misconduct policy to which MPs must adhere, but also decided the complainant’s claims were not “malicious”. The issue was referred to an independent expert group, when the complainant appealed – alleging the initial investigations were “unfair and inadequate”, according to a report published on Tuesday. But his appeal was rebuffed on the grounds that the expert group found the first investigation met a “sufficient standard” and the second was “very thorough”. A claim that investigators failed to speak to a “key material witness” was also dismissed, given the person “did no more than receive a hearsay account from an eyewitness”. Sweeney’s spokesperson said he is “considering the implications of the decision” and welcomed the first allegation about Thomson remaining upheld.