The Prince of Wales and the Home Secretary are expected to join hundreds of people for a service to mark National Police Memorial Day.
Prince Charles and Jacqui Smith will attend Liverpool's Anglican Cathedral alongside senior police officers and the families and friends of fallen officers.
During the service Joanne Terry, the wife of Greater Manchester Pc Ian Terry, 32, who was killed in June when he was shot in the chest on a training exercise, will light a candle in memory of her late husband.
The National Police Memorial Day and the service have been organised by the Police Roll of Honour Trust, which was founded five years ago to honour some 4,000 British police officers who have lost their lives while on duty since the first recorded death of a constable in 1680.
The trust was started by Pc Joe Holness after his colleague at Kent Police was killed while carrying out road safety checks.
It has brought together more than 20 years of research to create a national Roll of Honour for fallen police officers.
Prince Charles is patron of the National Police Memorial Day and Sir Ronnie Flanagan, the Chief Inspector of Constabulary, is patron of the trust.
After the service the prince will attend a reception where he will meet Mrs Terry, 31, and her children, Lauren and John, as well as other bereaved police families.
