A police officer walked in on an alleged lockdown Christmas party in Downing Street after an alarm was accidentally set off.
Deputy Met commissioner Sir Stephen House said the officer was spoken to by Sue Gray’s team during its investigation into illegal gatherings in No10 and will be spoken to by detectives leading the “partygate” probe.
He told City Hall’s Police and Crime Committee on Wednesday: “One officer was involved in responding with a civilian custodian, not one of [the Met] employees, who works for No10.
“[They responded] to a silent alarm which we believe had been pressed in error and that officer has been spoken to both by the Sue Gray investigation and will be spoken to by ourselves.”
The officer is believed to have gone to investigate the alarm with a doorman on December 18 2020. It is is alleged there was a party attended by up to 50 people going on at the time.
Sources have suggested the event took place in a room near No10’s main foyer when social gatherings were banned under Covid regulations.
The Met and Downing Street have both previously refused to confirm whether the officer attended the alarm.
Scotland Yard has sent questionnaires to more than 50 Downing Street staff asking them explain their attendance at 12 lockdown gatherings — up to six of which were reportedly attended by Boris Johnson.
The Met form suggests Mr Johnson has become the first British prime minister to be questioned under police caution.
Government staff were reportedly dispatched to local supermarkets to fill a suitcase with alcohol for boozy parties and a wine fridge was allegedly delivered to No 10 when restrictions were in place.
Sir Stephen said it had not been the job of parliamentary protection officers to intervene in alleged illegal gatherings.
Following reports Downing Street police had given “damning” statements about some of the alleged bashes, Sir Stephen told Greater London Authority members that “many of the events” being investigated took place at the “end of the working day” and involved people who had been in the building since “7 or 8am”.
“Parliamentary diplomatic protection officers are involved in the protection of Downing Street...They are not there to check people with No10 passes or parliamentary passes, they don’t check the contents of what they are carrying,” he said.
“It is not their job, they are there to protect against terrorist attack on No10 or people going in and out of No 10. There are not there to check what’s in people’s bags.
“This is a live investigation into events that took place at No10 and in the cabinet office but I think I can go as far as to say the vast majority of people who we have sent questionnaires to are people who work in those buildings and are already in the buildings.
“I think sometimes people have ideas that there [were] tipsy revellers walking down with Christmas hats on and blowing poppers carrying bottles of clanking wine.
“The point I’m making is many of the circumstances that we are investigating were events that took place at the end of the working day, or as an adjoin to the working day, with people who were already in the building who had been there since 7am or 8am.”
He added he expected the police investigation to be completed in weeks rather than months.
