Simon Harwood, the Scotland Yard officer accused of killing newspaper vendor Ian Tomlinson at the G20 protests in 2009, denies charges of manslaughter.
Appearing at Southwark Crown Court today, PC Simon Harwood showed no emotion as he stated his plea of "not guilty".
Ian Tomlinson's relatives gasped from the public gallery as PC Harwood denied the charges.
Mr Tomlinson, a 47-year-old newspaper seller, collapsed and died as he passed through the demonstrations in central London on 1 April, 2009.
His wife Julia wiped tears from her eyes during the hearing today, while Tomlinson's stepson Paul King muttered "No" to Mr Harwood's response. PC Harwood's wife Helen sat through the 20 minute hearing, showing no emotion.
PC Harwood was charged over Mr Tomlinson's death by the director of public prosecutions (DPP), after a review of an inquest jury's verdict of unlawful killing.
CCTV images, police helicopter footage and hand-held video recordings show Mr Tomlinson being hit by a police baton and staggering away from the crowd of protesters.
Media footage then shows Mr Tomlinson gesturing to police and appearing angry after falling to the ground.
His widow has said the death devastated her family, saying: "I remember feeling he was the best thing that ever happened to me."
PC Harwood is due to stand trial at Southwark Crown Court on 13 June next year.
15 April 2011