The Police Bravery Awards feature remarkable stories of officers - some of whom were off-duty at the time - risking life and limb to stop criminals in their tracks or rescue members of the public from almost certain death.
David Cameron, the Prime Minister, paid tribute to the nominees and thanked them for their "bravery and service in keeping us safe".
Heralding the sacrifice made by the two female officers in Manchester in September and Pc Ian Dibell, an off-duty Essex officer shot when he intervened in a dispute in July, the Prime Minister added: "The Police Bravery awards are a fitting tribute to some of the most extraordinary acts of courage and service this country has ever seen."
The 52 nominees from across England and Wales include:
* Pc Jacqui Ellis, from Dorset, who single-handedly tackled a knife-wielding woman who had earlier allegedly killed another person.
* Greater Manchester Police's Pc Gary Marshall, who was run over by armed men attempting to rob a security van. His actions foiled their robbery but led to the officer spending two weeks in hospital.
* Pc Alexander Stypulkowski, from Hampshire, who was stabbed in the head and neck with a screwdriver while detaining a man who had previously taken a woman hostage.
* Inspector Dennis Kelly, from Cumbria, who was on his way home from work when he saw a hooded man robbing a petrol station. He tackled the man, wrestled the gun away and called for back-up, leading to the suspect's arrest.
* Pc Aaron Horsfall, from West Yorkshire, who dragged three men from a burning house, even though two were heavily drunk and the third tried to attack him.
Paul McKeever, chairman of organisers the Police Federation, said: "These officers and their actions truly exemplify the fine model of British policing that is renowned worldwide and a service of which we are immensely proud."
The winners will be announced at a special ceremony, sponsored by Police Mutual, in central London on Thursday night.
