Tributes have poured into the UK after the tragic death of PC Andrew Harper, who was murdered while on duty last night.
10 people have been arrested, including a 13-year-old.
Thames Valley Police Federation said: "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.
"Sadly on very rare and horrendous occasions a colleague makes the ultimate sacrifice. We will ensure that heroism is never forgotten.
"We are offering our full support to the officer’s family and colleagues at this simply awful time."
Anthony Stansfeld, head of the PCC said: “I would like to offer my deepest condolences to the family, friends and colleagues of PC Andrew Harper. This is a tragic loss for the force and I know that Thames Valley Police are doing all they can to support those who have been affected."
Prime Minister Boris Johnson released a statement which read: "I am deeply shocked and appalled by the death of a brave officer on duty in Thames Valley last night. My thoughts are with PC Harper’s family, friends and colleagues at this terrible time.
"It is the most powerful reminder that police officers up and down the country put themselves at risk every single day to keep us safe. They have my absolute support."
There was widespread condemnation for this tragic act of violence across the political spectrum.
The leader of the Labour Party, Jeremy Corbyn tweeted: "Sending my condolences to PC Andrew Harper’s family and colleagues.
"For a police officer to be killed doing his duty is appalling. Whoever is responsible must be brought to justice."
Flags are currently at half mast across at various UK police forces headquarters, and TVP have changed their social media avatars to a black version of their crest.
Locally, Buckinghamshire County Council leader Martin Tett tweeted: Just heard about the sad death of PC Andrew Harper killed last night whilst on duty protecting the citizens of the Thames Valley.
"On behalf of the Councillors and Staff at Buckinghamshire County Council I would like to give my sincere condolences to his family and colleagues."
The Home Secretary, Priti Patel has released a statement which praised the amazing work police officers across the UK do.
"I’m devastated and appalled by the tragic death of PC Andrew Harper and my thoughts are with his loved ones, colleagues and the community he served with great pride at this immensely difficult time.
"PC Harper died in the line of duty protecting the public and his incredible bravery and extraordinary sacrifice will not be forgotten.
"Our dedicated police officers go to work every day to serve their communities.
"They are courageous and professional people who confront danger on a daily basis.
"The risks they take to keep us all safe are enormous.
"As Home Secretary, I’ll do everything in my power to support them and crack-down on the cowardly criminals who commit appalling acts of violence."