Sue Gray, the senior civil servant conducting the investigation, is reported to have received evidence of visits involving close friends of Carrie Johnson during lockdown.
Her inquiry is expected to be released this week.
However, the inquiry has now been widened to look into socialising at the prime minister’s Downing Street flat, the Sunday Times reported.
Ms Gray has discovered evidence that Ms Johnson welcomed two friends – both civil servants but not working at No 10 at the time – into her residence on several occasions during lockdown, according to the newspaper.
The visits were reportedly explained as being work-related.
Meanwhile, The Observer similarly reported that Ms Gray may have discovered details of another gathering at No 10, with rumours, it claimed, circulating in government this may have involved the PM’s flat and friends of his wife.
The newspaper also reported that Ms Gray, who is investigating at least nine Downing Street gatherings, has been granted access to security data showing staff movements in and out of the building – including information from swipecards.
On Saturday, Labour called on the prime minister to ensure the Partygate report is “published in its entirety”. It came after reports suggested some evidence – such as communications – could be withheld.
No 10 has been approached for comment by The Independent.
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