Sue Gray's report into lockdown-breaking parties in Downing Street is so damaging that it could leave Boris Johnson with no choice but to resign, senior officials are said to believe.
The top civil servant was forced to put off publishing her findings until Scotland Yard finishes its own investigation into rule-flouting gatherings in No10 and Whitehall.
Ms Gray's initial report into 16 lockdown parties, which was published in January, tore into "failures of leadership and judgement" in No10.
