Boris Johnson has said anyone who suspects he knowingly covered up lockdown parties in No 10 is “out of their mind”. The former prime minister said the claim was “strictly for the birds”, despite being under investigation for allegedly lying to parliament over lockdown breaches. He says he has been “respectful” to the Commons privileges committee investigation that is looking into whether he deliberately misled parliament. The seven MPs on the committee will assess if the former prime minister committed a “contempt of parliament”, which can be anything that blocks parliament from functioning properly. But in an interview with one of his most prominent Conservative backers, Nadine Dorries, on TalkTV, Johnson said: “But I’ll just repeat what I’ve said before, and I hope it’s obvious to everybody, that anybody who thinks I was knowingly going to parties that were breaking lockdown rules in No 10, or then knowingly covering up parties that were illicit that other people were going to, that’s all strictly for the birds,” he added. “And if anybody thinks like that, they’re out of their mind.” Johnson’s interview will be aired on Friday, during Dorries’ first show on the Murdoch-owned channel. Johnson also defended his team in Downing Street, claiming they were “thinking desperately” about Covid testing and the vaccine rollout at the time. “We all thought what we were doing – or certainly, I thought what we were doing – was within the rules. And what we certainly thought was that we were working blindingly hard on some massive priorities for the country,” he added. The former prime minister, forced out of office by the Conservatives after a series of scandals, is expected to give evidence to the inquiry in the coming months. He had repeatedly told the Commons there were no rule-breaking parties in Downing Street, and that the rules had been followed at all times. But the Metropolitan police issued 126 fines for breaches of Covid rules, including to Johnson, for offences spanning a series of gatherings in 2020 and 2021. The privileges committee has been sifting through a mound of written evidence handed over by Rishi Sunak’s Downing Street. If the committee rules Johnson did lie to parliament and a suspension of more than 10 sitting days is approved, he could face a challenging byelection in his Uxbridge and South Ruislip seat. A spokesman for the Committee told the Guardian: “The Committee has sent letters to individuals who may have knowledge relevant to the present inquiry regarding Boris Johnson MP, requiring them to provide evidence in writing. “The Committee requires the written evidence to be submitted by Tuesday 7th February. All written evidence submissions must be accompanied by a statement of truth. The Committee may have further requests to make for additional information.”