Scotland Yard is reopening its investigation into potential Covid breaches at a “jingle and mingle” lockdown party at Conservative headquarters at the height of the pandemic as the Partygate scandal continues to plague the Conservative party. The Metropolitan police’s decision to look again at the gathering of former Tory mayoral candidate Shaun Bailey’s campaign team in the run-up to Christmas 2020 has prompted calls to delay his peerage until the investigation is completed. The force will also scrutinise an event in parliament that the Tory MP Bernard Jenkin – a member of the privileges committee that produced a highly critical report into Boris Johnson lying to MPs over lockdown parties – is said to have attended. However, the Met and Thames Valley police said they would not open an investigation into 16 further alleged breaches involving Johnson, his wife Carrie and close friends at Downing Street and Chequers between June 2020 and May 2021. They said that having looked at the former prime minister’s official diaries, which were handed over to police by the Cabinet Office last month and are now the subject of a high court battle with the Covid inquiry, and later seeking “further clarification” about the entries, they had concluded the events did not meet the retrospective criteria. The Met will only investigate breaches of Covid regulations retrospectively when there is evidence of “serious and flagrant” infringements. However, in a statement, police said they “continue to reserve the right to revisit assessments in the event that further significant evidence comes to light”. Rishi Sunak faced pressure of his own over Partygate during an appearance in front of the powerful Commons liaison committee on Monday, where he sought to justify missing the vote on Johnson’s sanction and admitted he had not yet fully read last week’s brief report on attacks on the privileges committee by a series of Tories. The gathering in parliament on 8 December 2020, when London was under tier 2 restrictions, became the focus of a furious row between Johnson and Jenkin, the most senior select committee chair and one of four Tory MPs on the privileges committee. Johnson issued a scathing statement accusing Jenkin of “monstrous hypocrisy” for allegedly attending the event before sitting on the cross-party panel which found, after a year-long inquiry, that the former prime minister had lied to MPs with his Partygate denials. The event was believed to be a “drinks party” held by Dame Eleanor Laing, a Commons deputy speaker, in her office to celebrate the birthday of Lady Jenkin, the veteran Tory MP’s wife. Laing will not step down from her role while the investigation continues. Elena Ciesco, a spokesperson for Covid-19 Bereaved Families for Justice who lost her father on 8 December 2020, said: “To think that while I was saying goodbye to him over a screen, the people who were supposed to be protecting him were ‘jingling and mingling’ and treating the whole situation like a joke is beyond devastating.” The reopening of the investigation into the Conservative HQ event potentially plunges the Tory party’s London mayoral campaign into fresh turmoil, and comes after police considered footage from a video showing revellers at the event while the capital was under tier 2 Covid restrictions. The video, which was obtained by the Daily Mirror, shows Tory party workers drinking alcohol and dancing on 14 December 2020 at a campaign team gathering of the former mayoral candidate Bailey, who subsequently lost to Labour’s Sadiq Khan. Among those who appear in the video is Ben Mallet, Bailey’s campaign director, who is now running the campaign for Mozammel Hossain, a barrister on the shortlist to be the Tory candidate at next year’s London mayoral election. Bailey, who also attended and was pictured alongside the millionaire property developer and Tory donor Nick Candy in an earlier photograph of the event, apologised “unreservedly” after the video emerged. The Met had previously investigated the gathering but decided there was “insufficient evidence” to take further action. The Met police commissioner, Sir Mark Rowley, hinted last month that officers would reopen the inquiry into the event, as the new footage told a “much richer, clearer story” than the original photograph, and cast doubt on a previous statement that it was a “post-work event to thank campaign staff for their efforts over the course of the year”. \Bailey and Mallet, who is a close friend of Carrie Johnson, were handed a peerage and an OBE respectively in the former prime minister’s controversial resignation honours. Bailey has said it was for “others to decide” whether he should lose the peerage. The Liberal Democrats renewed their calls for Bailey’s peerage to be paused as police investigate the gathering. The party’s deputy leader, Daisy Cooper, said: “Rishi Sunak needs to confirm he will call for honours to be stripped from anyone found to have broken the law. “Anything less would make a complete mockery of his pledge to lead with integrity. He should also step in to stop Shaun Bailey from taking his seat as a peer while this investigation takes place.” The Met issued 126 fines over rule breaches in Whitehall and Downing Street while Johnson was prime minister, in a scandal that helped end his tenure in No 10. He and Sunak, then his chancellor, were among those to pay fixed-penalty notices. The Guardian reported earlier this month that Johnson and his wife, Carrie, hosted a close friend, who helped plan their wedding, overnight at Chequers when Covid restrictions were in place. Dixie Maloney, a corporate events organiser, stayed at the then prime minister’s grace-and-favour country mansion on 7 May 2021 when indoor gatherings between different households were banned except when “reasonably necessary” for reasons such as work or childcare.