A teenager has admitted killing a Thames Valley police officer.

Newlywed Andrew Harper, 28, died from multiple injuries after being dragged under a van on 15 August last year. The Thames Valley police officer had been on duty when he was killed near the village of Sulhamstead in Berkshire.

The alleged van driver, Henry Long, 18, from Mortimer in Reading, appeared at the Old Bailey for a plea hearing by video link from Belmarsh prison.

When asked for his plea to a charge of manslaughter, he said: “Pardon, was that manslaughter?” before adding: “I plead guilty, guilty.”

Long denied Harper’s murder but admitted conspiracy to steal a quad bike.

A 17-year-old co-defendant, who cannot be identified for legal reasons, entered not guilty pleas to Harper’s manslaughter and conspiracy to steal. The boy appeared in court by video link from Wetherby young offenders institute.

Another 17-year-old boy has previously entered not guilty pleas to manslaughter and conspiracy to steal.

A fourth defendant, Thomas King, 21, from Basingstoke, had admitted conspiracy to steal a quad bike. The three teenagers are due to face a six-week trial at the Old Bailey from 9 March.