A limited version of the report into No 10 and Whitehall parties during lockdown has criticised a “serious failure” to observe the high standards expected of those working at the heart of Government.

Sue Gray’s findings were published online as Boris Johnson prepared to face MPs at 3.30pm as he fights to save his premiership.

In a carefully-worded statement, the Cabinet Office said Ms Gray had provided an “update” on her investigation to the Prime Minister, suggesting it was not the full report she was preparing before the Metropolitan Police intervened.

Scotland Yard last week asked Ms Gray to make only “minimal reference” to gatherings being investigated by its officers.

Downing Street has so far refused to commit to publishing a fuller version of Ms Gray’s findings once the police investigation has concluded.

The version of Ms Gray’s report published online said “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”.

The Downing Street garden was used for gatherings “without clear authorisation or oversight” in a way that was “not appropriate”.

The report reveals 12 events are being investigated by the police, including a gathering in the Downing Street flat and an event to mark Boris Johnson’s birthday in June 2020.

While Ms Gray makes some broad findings about “failures of leadership and judgment” in parts of No 10 and the Cabinet Office, her report makes clear that the police investigation prevented more substantial findings being presented.

“As a result of the Metropolitan Police’s investigations, and so as not to prejudice the police investigative process, they have told me that it would only be appropriate to make minimal reference to the gatherings on the dates they are investigating.

“Unfortunately, this necessarily means that I am extremely limited in what I can say about those events and it is not possible at present to provide a meaningful report setting out and analysing the extensive factual information I have been able to gather.”