The killing of a Metropolitan Police officer in the line of duty is a "sad day for our country", the Home Secretary has said.

Priti Patel was among those to speak of their shock after an officer was shot inside a police station by a man who then turned the gun on himself in the early hours of Friday.

The victim died in hospital after the gunman, who was being detained, opened fire at Croydon custody centre in south London.

Speaking at the Home Office, Home Secretary Priti Patel said: "I'm deeply shocked and saddened by the tragic killing of the officer in Croydon overnight.

"All our thoughts are with the officer's family, friends and colleagues across the Metropolitan Police force, but also policing family across the country.

"This is a sad day for our country as once again we see the tragic killing of a police officer in the line of duty as they're trying to protect us and keep us safe.

"Later on today I'll be meeting with the Metropolitan Police Commissioner to discuss the investigation that is currently taking place, and of course the Metropolitan Police Service now need the time and the space to get on with the inquiry that now needs to follow."

In a statement, Scotland Yard said: "At approximately 2.15am on Friday, September 2,5 the officer was shot by a man who was being detained at Croydon Custody Centre in Windmill Lane.

"Officers and paramedics treated him at the scene and he was taken to hospital by London Ambulance Service. Very tragically he subsequently died at hospital.

"We are in the process of informing all of the officer's family and are supporting them with specialist officers.

"A 23-year-old man was detained by officers at the scene. He was also taken to hospital with a gunshot wound and remains in a critical condition.

"No police firearms were discharged during the incident."

Metropolitan Police commissioner Cressida Dick said: "This is a truly shocking incident in which one of our colleagues has lost his life in the most tragic circumstances. My heart goes out to his family, direct colleagues and friends.

"We are currently supporting his family and also have a dedicated team providing support to the officers and those in the custody centre who witnessed the shooting.

"When a colleague dies in the line of duty the shockwaves and sadness reverberates throughout the Met and our communities. Policing is a family, within London and nationally, and we will all deeply mourn our colleague.

"We are in the early stages of the investigation and are still working to establish the circumstances surrounding the incident and we will provide further updates when we have them."