Prince Charles joined about 1,500 officers, relatives and officials who gathered on Sunday to honour those who died or were killed on duty at the National Police Memorial Day (NPMD) service.
Home Secretary Priti Patel and Scotland's First Minister Nicola Sturgeon also attended the event at the Royal Concert Hall, where prayers were led and candles lit for UK force personnel who had made "the ultimate sacrifice".
The prince, patron of NPMD, was met upon arrival by a mounted police honour guard.
In a message in the order of service, Charles wrote: "In these difficult times, violent crime presents a significant threat not only to the safety of police officers and our communities, but also to the very fabric of our society.
"I particularly wish to remember the officers who have so tragically lost their lives in the line of duty since last year's ceremony in Belfast, and to offer my deepest sympathy to their loved ones, together with profound gratitude for their service."
More than 4,400 officers have died on duty since modern policing began.
Last month Pc Andrew Harper, 28, was killed near the village of Sulhamstead in Berkshire when he was dragged under a van while responding to reports of a burglary.
"A poignant reminder of the dangerous nature of policing"
National police chaplain Canon David Wilbraham said: "This special day gives us the opportunity to come together as a nation to remember our loved ones, friends and colleagues who have made the ultimate sacrifice while protecting the communities they served.
"It is an honourable day and a poignant reminder of the dangerous nature of policing."
Ms Sturgeon addressed the service and there were readings by Ms Patel and Scottish Justice Secretary Humza Yousaf.
Towards the end of the ceremony blue and green petals representing all officers who died on duty fell from the gallery.
Samantha Dixon from Thatcham, Berkshire, attended the service with her 18-month-old son Parker after losing husband James in a motorcycle accident in December 2017 when she was seven months' pregnant.
Mrs Dixon, 36, said: "I want him to have memories of how we recognised not only his dad but other officers as well.
"The ironic thing is he (James) would have loved all of this, because he was so proud to be a police officer and all it represented.
"He was full of fun, full of life, he lived life and so I want to do that for him, and I also want Parker to know that no matter what sadness hits your life, you can still make something of it and come out the other end fighting."
John Apter, national chair of the Police Federation of England and Wales, said: "Policing comes with a huge amount of risk and today is a stark reminder of just how precious life is.
"We will always remember the sacrifices made - we honour our brave officers and give our utmost respect to their loved ones who mourn their loss."
Chief Inspector Andrea MacDonald, chair of the Scottish Police Federation, said: "While this is a sombre event, I believe that it brings comfort to the families to know that they are part of the wider police family and that the sacrifice and bravery of their loved ones has not and will never be forgotten."
This year marks the 16th National Police Memorial Day, held annually on the nearest Sunday to St Michael's Day, the patron saint of police.