A teenage boy has denied killing a police officer who was run over while responding to a reported burglary.
The 17-year-old defendant pleaded not guilty to the manslaughter of PC Andrew Harper during a hearing at the Old Bailey in London.
The teenager, who cannot be named for legal reasons, also denied a charge of conspiracy to steal.
He was not asked to enter pleas to the further charge of murder.
Henry Long, 18, and a second 17-year-old boy have also been charged with murder, an alternative of manslaughter and conspiracy to steal a quad bike.
They did not enter pleas on Friday and another hearing was set for 7 January.
A fourth defendant, Thomas King, was accused of conspiracy to steal a quad bike over the same incident on 15 August.
The 21-year-old, from Basingstoke, pleaded guilty to the charge and was granted bail until his sentencing at the conclusion of proceedings against the other defendants.
A six-week trial is due to start at the Old Bailey on 9 March.
PC Harper, a Thames Valley Police officer, was killed on 15 August near the village of Sulhamstead in Berkshire.
The 28-year-old died from multiple injuries after being dragged under a van, four weeks after his wedding.
Additional reporting by PA