Police forces across the UK have shared their grief following the death of an officer who was killed while performing his duties last night.
PC Andrew Harper, 26, died after reportedly being hit by a car when he was called to a burglary at 11.30pm near the A4 between Reading and Newbury.
A murder probe has been opened and 10 people have been arrested.
In a statement Thames Valley Police said PC Harper was "killed while performing his duties".
The tragedy sparked an outpouring of grief from police forces across the country, with colleagues saying they stand "shoulder to shoulder" with Thames Valley officers.
Lancashire Police wrote on Twitter: "Our thoughts are with the friends and family of PC Andrew Harper and all our colleagues @ThamesVP at this desperately sad time. Andrew was killed on duty last night. The police family in #Lancashire stands shoulder to shoulder with you all."
And the Metropolitan Police Marine Service wrote: "Our most sincere condolences are with the family and friends of PC Andrew Harper of who tragically paid the ultimate price while undertaking his Policing duties last night. Rest in Peace Constable."
The South Wales Police Roads Policing Unit wrote on Twitter: "Sending our love and thoughts to the family of PC Andrew Harper."
West Yorkshire Police wrote: "Sending our condolences to the family of PC Harper and colleagues at @ThamesVP after hearing of today’s terrible news."
Suffolk Police posted: "Sad to hear about the death of PC Harper. Our thoughts are with his family and colleagues at this awful time."
Surrey Police wrote: "Shocked and saddened to hear of the death of one of our @ThamesVP colleagues last night. Our thoughts are with all those who knew PC Harper."
In a statement the Thames Valley Police Federation - which represents rank-and-file officers - said: "This is totally devastating news.
"All our thoughts - and the thoughts of the entire police family across the UK - are with the family, friends and close colleagues of PC Harper who died last night.
"Police officers go to work each and every day to do their duty. We are courageous, caring and compassionate.
"We confront danger on a daily basis. We know there is a risk when we put on the uniform but we do so as we are proud to protect the public."
Cumbria Roads Police wrote: "Today our thoughts are with PC Andrew Harper’s family, friends and colleagues at @ThamesVP The police family stands with you."
Home Secretary Priti Patel wrote: "My thoughts are with the family of PC Andrew Harper who was killed in the line of duty last night."
And Shadow Home Secretary Diane Abbott posted on Twitter: "Incredibly saddened to hear about the events that took place in Berkshire last night. All my thoughts are with the family, friends and colleagues of the courageous PC Andrew Harper who was killed in the line of duty."
The incident happened at the crossroads of Ufton Lane and Lambdens Hill, near to Sulhamstead, a village in West Berkshire.
Deputy Chief Constable Jason Hogg said: “Our deepest thoughts at this time are of course with Andrew’s friends and family, who are being supported by specially trained family liaison officers.
“Our thoughts also extend to all of Andrew’s colleagues within Thames Valley Police.
“As a force we are devastated at the loss of our colleague and will all be supporting each other at this difficult time.”
Senior investigating officer Detective Chief Inspector Stuart Blaik, of the Thames Valley Police Major Crime Unit, said: “This is a tragic incident, and I would like to reassure the public as well as our officers and staff that we have launched a full and thorough investigation to establish what has happened.
“We have made a total of ten arrests in connection with this incident, and those arrested are currently in police custody. Those arrested are all male and aged between 13 and 30."
Prime Minister Boris Johnson said he was "deeply shocked and appalled" by PC Harper's death.
