Met issues guidance on plain-clothes officerspublished at 13:45 British Summer Time 1 October 2021
Here is a bit more detail on the response to the murder of Sarah Everard, who was kidnapped in a fake arrest by a serving Metropolitan Police officer.
Scotland Yard has issued some advice to people on how to deal with plain-clothes officers.
The force says people detained by a lone plain-clothes officer should ask "searching questions" such as why they are being stopped, where the officer's colleagues are and where the officer has come from.
The force says that, to verify the answers, people should ask to speak to an operator on a police radio to determine if the officer is genuine and acting legitimately.
In the event someone believes they are in "real and imminent danger" the Met advises they "must seek assistance - shouting out to a passer-by, running into a house, knocking on a door, waving a bus down or if you are in the position to do so, calling 999".
The Met explains officers are expected to intervene when required, even when off duty, and that they routinely carry warrant cards and sometimes equipment when travelling.
Speaking to the London Assembly, Met Deputy Commissioner Sir Stephen House, says plain-clothes officers will not be deployed on their own and will be in pairs.
But he warns there will be occasions when that is not possible given that off-duty officers not in uniform "put themselves on duty" when they come across an incident.