Two teenagers due to go on trial for the murder of a police officer dragged under a car have admitted conspiracy to steal a quad bike.

The 17-year-olds, who cannot be named, pleaded guilty to plotting to steal the bike at the beginning of their trial at the Old Bailey on Monday.

A third suspect, Henry Long, 18, from Mortimer, Reading, had already admitted conspiring to steal the quad bike.

All three have denied murder, but Long has admitted manslaughter. The 17-year-olds deny manslaughter.

They had tried to steal the quad bike from a home near the village of Sulhamstead, Berkshire, on 15 August last year.

Harper, who was 28 and had just got married, had arrived at the scene to investigate a suspected burglary. He died after he was dragged under a car, inflicting multiple injuries.

Within an hour of the incident, police had arrested 10 suspects.

Brian Altman QC is to open the case for the prosecution on Tuesday. The trial, before Mr Justice Edis, is due to go on for up to six weeks.

Thomas King, 21, from Basingstoke, has already pleaded guilty to plotting to steal a quad bike and is waiting on bail to be sentenced at the conclusion of the other defendants’ trial.