Boris Johnson has said it was “a total mistake” to try to defend Owen Paterson from punishment for repeatedly breaking lobbying rules, adding that he fully accepted that what his former Conservative colleague had done was wrong. In a sometimes uncomfortable appearance before the Commons liaison committee, Johnson said his brief attempt unilaterally to replace the existing disciplinary system for MPs with a new, Tory-majority committee, had happened after unnamed “colleagues” told him it would have cross-party support. “I believed that there would be cross-party support for the idea,” Johnson told Chris Bryant, the Labour MP who chairs the Commons standards committee, who reminded the prime minister that this had turned out not to be the case. “So it would seem,” Johnson replied. Asked why he believed other parties would back the plan, Johnson said: “It was put to me by colleagues.” In his most thorough admission of error since sparking two weeks of intense focus on paid lobbying and other secondary employment by MPs in trying to rewrite the disciplinary rules, a plan reversed a day later amid an outcry, Johnson said he had also been influenced by the personal circumstances of Paterson, whose wife had killed herself last year. “Yes, I think it was a total mistake not to see that the former member for North Shropshire’s breach of the rules made any discussion about anything else impossible. And I totally accept that,” Johnson told the liaison committee, a super-committee comprising the chairs of subject-specific select committees, which is tasked with questioning the prime minister three times a year. “I think it was a very sad case, but I think there’s no question that he had fallen foul of the rules on paid advocacy, as far as I could see from the report,” Johnson said. “I think the question that people wanted to establish was whether or not, given the particularly tragic circumstances, he’d had a fair right to appeal.” Challenged on the idea Paterson had not had a proper appeal by Bryant, whose committee had heard the appeal, Johnson backed down. He said: “In forming the impression that the former member for North Shropshire had not had a fair process, I may well have been mistaken, but that was certainly the impression that many people seemed to have.” Separately, Johnson indicated it was he who had ordered Kwasi Kwarteng to apologise to Kathryn Stone, the parliamentary commissioner for standards, for suggesting in an interview she should resign after a government-led Commons vote had briefly overturned her sanction against Paterson. Saying the apology was “something that was generated in the course of consultation between me and Lord Geidt”, his adviser on ministerial interests, Johnson emphasised that it was not Geidt who had ordered the apology. Johnson also resisted calls from several MPs on the committee, including the chair, the Tory MP Bernard Jenkin, for Geidt to be given the independent right to begin investigations into ministerial wrongdoing, rather than needing prime ministerial approval. “I think it’s highly unlikely that I would in any circumstances disagree with him,” Johnson said. Asked why, then, he would not give Geidt independent powers, Johnson replied: “I think the system that we have is the one that I inherited and it seems to work pretty well.” Questioned by Yvette Cooper, the Labour MP who chairs the home affairs committee, Johnson said he fully accepted that Paterson had done wrong, answering: “Yes, I do.” He also accepted error in being pictured not wearing a mask during a visit to a hospital in Northumberland last week, while telling Cooper that this had been brief. “As for not wearing a mask in Hexham hospital, which you wrap up into my general litany of crime, can I just say that actually, it was barely 30 seconds when I wasn’t wearing a mask,” he said. “I walked out of a room, mistakenly not wearing it, I then put it on as soon as I realised I’d made that mistake. I apologise for it, but most pictures of my visit to the hospital will show that I was duly masked throughout the remainder of the visit.”