Retired Metropolitan Police officers are being asked to return to the force as it tries to cope with the coronavirus outbreak in London.
Former PCs and sergeants who left in the past five years are to be offered work in a paid or voluntary capacity.
The force also wants those nearing retirement to consider staying on.
Met Commissioner Cressida Dick said: "Demands on us will grow and vary over the coming weeks but I want people to know and see the Met is here for them."
She is writing to retired police constables and sergeants to re-join at those ranks, either on a full or part-time basis.
The latest available Home Office data shows 5,012 Metropolitan Police officers retired in the five years up to March 2019, excluding those who did so on medical grounds.
The force had a total of more than 31,000 officers as of last September.
Senior officers may be able to return to service where they bring specific skills and experience.
The Met also wants retired officers to sign up as special constables.
What do I need to know about the coronavirus?
Officers who retired at the rank of inspector or above are being asked to consider joining the special constabulary for at least 16 hours a month, or they can volunteer in other roles.
Ms Dick said: "Police officers overwhelmingly join 'the job' to help people and to make a difference, and that desire will be as strong today as it was the very first day they joined.
"I am hopeful that these exceptionally experienced and knowledgeable former colleagues choose to come and be part of our team and support London at this extraordinary time."
The Met said those wishing to return would be asked to complete an online form and must be sponsored by a serving Met officer.
It said it was waiting to receive "confirmation that the added costs will be met by government".
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