The jury in the trial of three teenagers accused of the murder of PC Andrew Harper has been discharged after three jurors placed themselves in self-isolation due to the coronavirus pandemic.
The 28-year-old Thames Valley officer died after he was dragged behind a car driven by suspected thieves while responding to an emergency call near Sulhamstead in West Berkshire last August.
Henry Long, 18, and two 17-year-old boys, who cannot be named for legal reasons, were charged over his death, but their murder trial has now been adjourned after the jury of 12 men and women was depleted due to the COVID-19 pandemic.
Mr Justice Edis told the court on Monday that he had made the decision with a "heavy heart" after a third juror went into self-isolation over the weekend, following two others last week.
"It is with great regret that I have decided to discharge the jury and to adjourn this trial," said the judge.
"I have taken this decision with a heavy heart because I am acutely conscious of the need of those who loved Police Constable Harper, who would have been 29 yesterday, for this process to come to a conclusion."
A review hearing is set for 1 June for the judge to set a new trial date, with the defendants to remain in custody until then.
Long, of Mortimer, Reading, has admitted manslaughter and conspiracy to steal a quad bike but denied murder.
The two other teenagers admitted conspiracy to steal but denied murder and manslaughter.
Jurors heard last week that PC Harper's legs became entangled in a tow rope as he tried to apprehend quad bike thieves.
He was probably knocked unconscious as he fell, then dragged for more than a mile along country lanes behind a Seat Toledo driven by Long, the court was told.
Colleagues desperately tried to save him but he suffered "absolutely catastrophic, unsurvivable injuries" and died at the scene.
Over the past two weeks, the jury viewed harrowing dash-cam footage and heard several eyewitness accounts, with one witness describing how he first mistook PC Harper's body for a bloodied deer being dragged behind a car.
The trial was among eight at the Old Bailey that continued last week despite the pandemic, while more than a dozen high-profile trials at the UK's top criminal court had already been postponed.