When I heard about the murder of a police officer at Croydon custody centre last Friday it felt personal.

My brother was a detective inspector at Croydon in the early 1990s and I have worked closely with our police at Torquay custody centre as a police surgeon. I understand the pressures and dangers officers face on the front line.

This is not a one-off. He is the 12th British police officer to lose his life in the line of duty in the last ten years.

These tragedies include the death of PC Andrew Harper, dragged behind a car while investigating a burglary, PC Keith Palmer, stabbed to death outside the Houses of Parliament and PC David Philips, run over by a suspect after a high-speed chase.

Sadly, we can now add the name of Matiu Ratana, a custody sergeant.

All these occurred during routine police work. The officers were not involved in areas of policing known to be high risk. They were not undercover or armed.

And this latest tragedy was also during the routine work familiar to any officer.

Although we have seen police violence and deaths in America on our TV screens, the UK is not America.

In the USA in 2019 there were 34.8 people killed per ten million of the population by intentional use of force when a police officer was present; in the UK the figure is 0.5.

Many people taken into police custody behave well but there are occasionally some very violent people who I had to see through hatch on the cell door. It would be too dangerous to carry out a proper medical assessment.

One man, high on amphetamines, attacked the police with a samurai sword. They could only restrain him using shields and, in those days, CS gas spray. He was also my patient.

The following day a social worker rang me and accused the police of excessive violence. I explained that I had been there and seen the police restraint. The only excessive violence came from her client.

It is easy to come in the next day and accuse the police of undue force.

Officers used to talk about the nine o’clock jury.

At three in the morning with a custody centre full and some very violent offenders, the pressure is on. At the same time, the staff are dealing with medical and social problems.

In the custody centre people were referred to drug treatment programmes. I was also working with psychiatrists to help people with mental health issues.

Luckily, I never came across firearms. We live in one of the lowest crime areas in the country.

In one of my training courses I saw a demonstration of modern firearms. It is no use hiding behind a car door which happens in some police dramas. Bullets will even penetrate a breeze block wall.

A firearms officer showed an interactive training video with one of my fellow doctors acting as a policeman.

Suddenly on the video a car pulled up and men ran out firing guns. The doctor, acting as the policeman, shouted a warning and then fired back. He missed.

In the debrief, the firearms officer pointed out that, behind the ‘villains’ was a school playground full of young children. If this had been a real scenario he would have missed the criminals but killed several children.

But the main purpose of policing in the UK is to work with the public to prevent crime. We can go right back to Robert Peel who founded the Metropolitan Police in 1829. He argued for policing by consent.

In his view, police officers were members of the public in uniform or, as he put it, the police are the public and the public are the police.

When an officer is killed, we have not only lost a member of the police family. The tragedy is wider. On Friday, we all lost a member of our family. The tragedy in Croydon was personal.