Tributes were paid to the policeman who was shot dead after intervening in a "deadly situation" in a seaside town.
Sir Hugh Orde, President of the Association of Chief Police Officers, was among senior policemen who hailed Pc Ian Dibell's bravery after he was killed while attending an address in Clacton, Essex, yesterday.
Pc Dibell had been off-duty at the time.
Sir Hugh said: "The death of our colleague in Essex is deeply sad news for the police service. Pc Ian Dibell died while knowingly walking towards danger, as police officers are called upon to do on behalf of the public they serve.
"The courage he showed in stepping up to do his duty, without thought for his own safety, sums up what it means to be a police officer. The thoughts of everyone in the police family are with his colleagues, family and friends at this difficult time."
Essex Police Chief Constable Jim Barker-McCardle told a press conference at the force's Chelmsford headquarters that Pc Dibell was a "brave, respected and experienced neighbourhood officer".
Mr Barker-McCardle said the officer had "deliberately intervened in what he knew was an extremely deadly situation", adding:
"Our thoughts and prayers are with the family of our brave, fallen colleague."
The chief constable continued: "Policing is a family and we are all hurting.
"This dreadful event reminds us all that policing is a mission that ultimately some die for.
"We will not rest until his killer is found."
Paul McKeever, chairman of the Police Federation of England and Wales, also paid tribute to Pc Dibell, saying: "This is extremely tragic and devastating news. Police Constable Ian Dibell demonstrated remarkable courage and bravery whilst off-duty and has paid the ultimate price.
"The thoughts of the entire police service are with his family, friends and colleagues at this very difficult time."
Mark Smith, chairman of the Essex Police Federation, added: "This is a terrible tragedy and our thoughts and prayers are with Pc Ian Dibell's family, friends and colleagues at this extremely sad time.
"Constable Ian Dibell was a dedicated professional officer who, even though off duty, has paid the ultimate sacrifice for his bravery and selfless actions in trying to protect his local community.
"This appalling incident highlights the dangers that police officers face every day.
"No words can help those closest to Pc Dibell at this terribly distressing time but I hope they will find some comfort in knowing that the loss of this brave man is mourned by the entire police family throughout the United Kingdom."
Chief Superintendent Irene Curtis, president-elect of the Police Superintendents' Association of England and Wales, said her thoughts were with Pc Dibell's "family, friends and colleagues, and the communities of Clacton who will be shocked and saddened by this tragedy".
"We are all fully aware of the courage and bravery often demonstrated by police officers, but it is sometimes forgotten that police officers have a responsibility to protect the public at all times," she said.
"Even though he was off duty, Pc Dibell was apparently fulfilling this duty and he has paid the ultimate price, giving his life to protect others."
Hampshire Police Fed
Insp Dave Meredith
The Urban WPC