A long-serving police officer has been shot dead at Croydon Custody Centre in south London.
The male sergeant was shot in the chest before the suspect turned the firearm on himself.
The man had been brought to the custody suite in a police vehicle and the shooting happened during questioning about Covid-19.
A minute’s silence has been held for the officer described by the Met Police chief as a “much-loved colleague”.
The victim, who has not been named, is thought to have been a few weeks away from retirement and was described as “one of a kind” by a colleague.
The suspect is believed to be critically ill in hospital.
The Mayor of London Sadiq Khan said the police were currently “reviewing the safety of custody suites” and “there could be changes very soon to custody suites to make sure they are as safe as they can be”.
Earlier, Prime Minister Boris Johnson said: “We owe a huge debt to those who risk their own lives to keep us safe.”
In a post on social media he also said: “My deepest condolences go to the family, friends and colleagues of the police officer who was killed in Croydon last night.”
A number of police officers have also been turning their social media profile pictures black with a blue stripe to pay their respect to the officer.