A key member of Carrie Johnson’s inner circle could be hauled before MPs to reveal details about an “Abba party” in Boris Johnson’s private flat.

       Henry Newman, a former Number 10 special adviser who now works for Michael Gove, faces a summons by Parliament’s privileges committee, which is investigating whether Mr Johnson knowingly misled the Commons over partygate.

       Mr Newman is Mr Johnson’s alibi for the gathering on Nov 13, 2020, because the Prime Minister claims he was interviewing the adviser rather than taking part in a social event.

       Others have claimed Mrs Johnson organised the event to celebrate the departure of Dominic Cummings and Lee Cain from Downing Street, and sang along to The Winner Takes It All with five political staff.

       Downing Street sources have denied the claims and say they were fabricated in an attempt to discredit Mrs Johnson.

       Sue Gray’s official inquiry did not fully investigate the party, despite claims it was the most likely to implicate Mr and Mrs Johnson in partygate, because she did not believe it was “proportionate”.

       Now the issue is set to be examined by the privileges committee to determine whether Mr Johnson could have known gatherings were against the rules.

       A source close to the committee told The Telegraph that Mr Newman or any other attendee could be hauled in front of MPs to explain what happened that night.

       “Anybody can be made to give evidence by a parliamentary committee. Spads and MPs and anybody,” the source said, adding that Mr Johnson was unlikely to attempt to block their appearance.

       “It’s like a contempt of Parliament in such a set of circumstances, and I would have thought the last thing the PM wants to have is a row with the privileges committee.”

       All three parliamentary private secretaries on the committee, who have government roles, have resigned their posts to begin the investigation.

       If Mr Newman was to reveal more information about the nature of the event and its attendees, it could implicate Mr and Mrs Johnson in another partygate event.

       The committee could also request that Ms Gray herself gives evidence, or releases more of the 300 photographs her investigation collected. So far, just nine have been published. It could also request evidence from Met Police detectives.

       Mr Johnson has been named as attending several of the 16 gatherings Ms Gray investigated, and he and his wife were fined for attending an impromptu birthday party for him in June 2020.

       Two sources who have spoken to Ms Gray about her decision not to further investigate the flat party said she did not believe it would be necessary because the Metropolitan Police had already examined it as part of Operation Hillman.

       But others have speculated that she did not believe the five special advisers in the room would go on the record to give evidence about Mr Johnson and his wife.

       Mr Newman declined to comment.