Police investigating party in Boris and Carrie Johnson’s flat

A party in Boris and Carrie Johnson's flat is one of 12 events being investigated by the Metropolitan police over alleged lockdown breaches, it has emerged, as the Sue Gray report found "failures of leadership and judgment" in No 10.

Gray, a senior civil servant, criticised the culture in Johnson's Downing Street that allowed social gatherings to take place during lockdown, which were "difficult to justify".

The findings were released on the government's website in a shortened and redacted form, after the Met last week said it was investigating some of the gatherings.

Although Gray said she was not able to publish her full report, a string of Conservative MPs said the conclusions were still extremely serious for Johnson - not least because one of the gatherings under police investigation was in the prime minister's apartment.

In the Commons, Johnson was challenged by Theresa May, his predecessor as prime minister, who said either he "had not read the rules, didn't understand the rules, or didn't think they applied to No 10".

Andrew Mitchell, a Tory MP and former cabinet minister, said Johnson "no longer enjoys" his support.

And in a dramatic moment, Ian Blackford, the SNP Westminster leader, accused Johnson of having "lied and misled" the house of Commons and was ejected from the chamber by the Speaker.

Johnson had previously denied in the House of Commons that any party on 13 November, 2020, had taken place. Johnson was also present at another of the parties under investigation by police - in the Downing Street garden on 20 May, 2020.

Johnson rejected these criticisms in turn but promised that he would overhaul the structure of No 10 to address some of Gray's criticisms. "I get it and I will fix it," he told MPs.

In the report, Gray did not criticise the prime minister personally, or pass judgment on his past statements, but highlighted failures of leadership in No 10 and the Cabinet Office.

The 12-page report said: "At least some of the gatherings in question represent a serious failure to observe not just the high standards expected of those working at the heart of government but also of the standards expected of the entire British population at the time."

It added: "At times it seems there was too little thought given to what was happening across the country in considering the appropriateness of some of these gatherings, the risks they presented to public health and how they might appear to the public.

"There were failures of leadership and judgment by different parts of No 10 and the Cabinet Office at different times. Some of the events should not have been allowed to take place. Other events should not have been allowed to develop as they did."

Gray listed 16 gatherings on 12 dates across 20 months in 2020-21 that she had examined for evidence of rule-breaking, of which 12 are being investigated by police. These include a gathering in the No 10 flat - thought to be a reference to the prime minister's own residence even though he lives at No 11 - and a Christmas party in Downing Street, as well as several leaving parties.

The civil service chief said she had interviewed more than 70 people and examined relevant email information, WhatsApp messages, photographs and exit logs. She said some staff had "wanted to raise concerns about behaviours they witnessed at work but at times felt unable to do so".

"A number of these gatherings should not have been allowed to take place, or to develop in the way that they did. There is significant learning to be drawn from these events which must be addressed immediately across government."

Gray said her report was limited by the Met police request for her to make only minimal reference to gatherings they were investigating. She said she had decided not to publish factual accounts of the other four dates as she did not feel able to do so without detriment to the overall balance of findings.

However, she left the door open to returning to the evidence she gathered after the Met police had investigated, saying it was being stored and saved "until such time as it may be required further".

Earlier on Monday, No 10 had said it was "unclear" whether she would publish a further, more comprehensive, report in the future.