LONDON — A police officer who knocked part of a man’s tooth out with his riot shield during a student protest in 2010 has been sentenced to eight months in prison.

PC Andrew Ott, 36, struck William Horner as the Royal Holloway student tried to break free from a kettled area on Parliament Square in central London.

Ott was found guilty on Tuesday of one count of assault occasioning actual bodily harm, but cleared of perverting the course of justice.

At Southwark crown court on Wednesday, Ott sobbed in the dock as he was sentenced.

The judge Jeffrey Pegden told him he had carried out “gratuitous and unnecessary violence” and abused his power as a police officer.

He said: “This offence was committed in a sterile area, in relative darkness, when you had the victim cornered and no violence was necessary at all. An extremely serious aggravating factor is your abuse of power as a police officer.

“You hit him with a full-force blow to his face with your shield. That was wholly gratuitous, unnecessary violence, and I have considered the stress on William Horner over the last few years.”

Ott wiped his eyes with a tissue, and a woman in the public gallery broke down in tears after the sentence was passed.

Ott’s colleagues PCs Calvin Lindsay and Thomas Barnes were cleared of perverting the course of justice.

Jurors heard that Ott was taped on his personal recording device threatening violence towards the crowds that had gathered near the Houses of Parliament and talking about “getting” the protesters.

Ott, from Rochester, Kent, chased Horner as he tried to scale a fence, and was captured on the audio device

saying “poked the little cunt right in the eye” and “I’ve had enough of these cunts, I just fucking hit him”.

During the protests, riot police were pelted with missiles, including rocks and concrete blocks, and statues in Parliament Square were daubed with graffiti. No action was taken against Horner, who was 20 at the time.

The judge said he had no doubt that policing the protests on 9 December 2010 was “frightening, stressful and exhausting”.

However, he said Horner had “simply wanted to go home” and had not committed an offence when he was attacked.

In mitigation, Kevin Baumber said his client had been diagnosed with depression and suffered from severe stress.

He told the court: “Your honour may think on that day he was pushed into losing his normally sound judgment in what was a long, tiring and terrifying day. It was a day that was traumatic. It was a trauma that still lives with him.”

Ott, who has served as a police officer since 2003, faced the “double jeopardy” of criminal proceedings and disciplinary action and was in danger of losing a career “that is dear to him”, Baumber added.

An investigation by the Independent Police Complaints Commission found all three officers have a case to answer for gross misconduct, and they will face Metropolitan police disciplinary hearings.

Deputy assistant commissioner Fiona Taylor, of the Met’s directorate of professionalism, said: “We are naturally disappointed that an MPS officer has been convicted of an assault.

“His behaviour clearly fell well below the high standards we expect of our officers, even in challenging circumstances such as the violent disorder in which this incident occurred, and it is right that he was held to account in the criminal courts.

“His case and that of the other two officers involved will now be subject to the misconduct process. Until this is completed it would be inappropriate for us to comment further.”

This story originally reported by The Guardian