The Metropolitan Police responded to a silent alarm that was accidentally set off during a Downing Street party, the deputy commissioner has confirmed.
Sir Steve House told the London Assembly police and crime committee that an officer involved in the incident was being spoken to.
“One officer was involved in responding with a civilian custodian who works for Number 10 to a silent alarm, which we believe had been pressed in error,” he said on Wednesday.
“That officer has been spoken to both by the Sue Gray investigation and will be spoken to by ourselves.”
Sir Steve was questioned on why the officers assigned to protect Downing Street had not prevented alleged lawbreaking at the events now under criminal investigation.
“If we find officers knew what was going on and should have intervened we will follow up on that,” he said.
Sir Steve said officers were assigned primarily to protect the building, and that armed police on the gates are “not there to check people with Number 10 or parliamentary passes” but to prevent terror attacks.
The deputy commissioner said the officers do not perform bag checks on staff, and that the vast majority of people under investigation were “people who work in those buildings”.
“Many of the circumstances we are investigating were events that took place at the end of working day or as an adjunct to the working day with people who were already in the building,” Sir Steve told the committee.
“Armed officers do not routinely walk through the Cabinet Office or Number 10.”
ITV news previously reported that a silent alarm was set off during Downing Street’s 18 December 2020 Christmas party.
Scotland Yard has sent questionnaires to more than 50 people, including the prime minister, accused of attending events that violated the Covid laws in place at the time.
Responses are being treated as answers given under caution, and anyone who is not able to demonstrate a reasonable excuse in law can be fined.
Sir Steve said the investigation was expected to take weeks, rather than months, but that more questionnaires could be sent out to any new suspects identified by responses.
The Metropolitan Police is investigating 12 events, including as many as six which the prime minister is reported to have attended.
It follows allegations of frequent and excessive drinking by Downing Street staff, to the extent where a wine fridge was purchased and staff were dispatched to local supermarkets to fill a suitcase with wine.
Boris Johnson has completed the questionnaire in relation to alleged parties, which the Met previously said had “formal legal status and must be answered truthfully”.
