Tributes have been paid to Pc Andrew Harper’s “bravery” and “sacrifice”, following the conviction of three teenagers over his brutal death as he investigated a crime.

The 28-year-old newlywed has been described as a “brave hero”, killed while doing his job.

The conviction of Henry Long, 19, Albert Bowers and Jessie Cole, both 18, for manslaughter following a trial at the Old Bailey, brings “some justice”, Thames Valley Police Chief Constable John Campbell said.

But Pc Harper’s widow Lissie, speaking outside court, said she was “immensely disappointed” by the verdict, after the jury cleared the trio of murder.

Describing him as a “beautiful, loving, decent human being”, she said her new life without him would be “a lot more painful” and “soul destroying” than that of anyone facing a “meagre number of years” in jail.

Chief Constable Campbell paid tribute to Pc Harper’s family, saying: “They have been through something that no family should ever have to face, but they have shown the most incredible dignity and bravery every step of the way and they have had to do all of this in the public eye.”

He added: “Today we have some justice for Andrew, but I know nothing will ever take away the sense of loss for those who loved him. None of us will ever forget Andrew Harper’s sacrifice and we are proud to have called him our colleague and our friend.”

Craig O’Leary, chairman of Thames Valley Police Federation, said a future which should have consisted of a “long and loving marriage and a highly successful career” had been taken from the officer by “cowardly criminals”.

He added: “Sadly on very rare and horrendous occasions a colleague makes the ultimate sacrifice. When that happens, we must ensure they are never forgotten – and in Thames Valley Police we shall never forget Andrew or his bravery that night.”

Senior investigating officer, Detective Superintendent Stuart Blaik of the Thames Valley Police Major Crime Unit, said the force respected the jury’s decision to find the three defendants not guilty of murder, adding: “No matter what the verdicts, there would have been no sense of victory.”

He said: “Pc Andrew Harper was a brave, young, dedicated police officer who was killed in the act of doing his job and trying to protect the public.

“Thames Valley Police, the wider policing family, and the country as a whole is proud of Pc Harper for his dedicated service to protect the public, which ultimately cost him his life. We are all honoured to have called him our colleague.

“He will always be remembered.”

Jaswant Kaur Narwal, chief crown prosecutor for Thames and Chiltern, said: “This is a truly heart-breaking case in which a young police officer with everything to look forward to tragically lost his life in the line of duty.

“He was killed trying to stop suspects who were prepared to go to any lengths to get away with their crime.”

She said following an “emotional trial” she was “pleased the jury has found all three culpable for Pc Harper’s death”.

Senior crown prosecutor Rebecca Waller said the verdicts marked the end of an “extremely difficult trial” for Pc Harper’s family, friends and colleagues.

She paid tribute to the officer’s loved ones who had shown “great strength, courage and integrity”.

She added: “We are really pleased to say that the three people responsible for Pc Andrew Harper’s death have been convicted.”