He struck student William Horner when he tried to leave 'kettled' area

A police officer who knocked a student's tooth out with his riot shield during the 2010 student protests has been jailed for eight months.

PC Andrew Ott, 36, was taped threatening to 'batter' protesters at the demonstration in central London and telling a colleague he had 'just had enough of these c****'.

And when Royal Holloway student William Horner, then aged 20, tried to leave the 'kettled' area on Parliament Square, the officer struck him with his riot shield, knocking his front tooth out.

Scroll down for videos

When student William Horner, then aged 20, tried to leave the 'kettled' area on Parliament Square, PC Andrew Ott struck him with his riot shield, knocking out his front tooth (as seen in the police footage above)

The assault happened after Ott, of Rochester, Kent, chased Mr Horner as he tried to scale a fence near the Houses of Parliament.

The violent protests saw riot police pelted with missiles, including rocks and concrete blocks, and statues in Parliament Square were daubed with graffiti.

Audio recordings taken from a device worn by Ott captured the student as he accused the police officer of breaking his tooth, to which Ott responded, 'not me mate, you slipped on a metal fence'.

Video footage taken by a police photographer that night shows Mr Horner pointing towards his missing tooth and asking the camera man to 'get the number' of the officer detaining him.

Jurors heard that Ott was also taped threatening violence towards the crowds that had gathered and talking about 'getting' the protesters.

Speaking later to another officer about Mr Horner, Ott said: 'I've had enough of these c****. I just f****** hit him', the court heard.

When student William Horner, right outside court earlier this month, initially accused Ott, left outside court, of assaulting him, the police officer replied 'not me mate, you slipped on the metal fence', the court heard

Footage taken from a police helicopter on the night of the demonstration shows protesters (seen as black marks) gathering in Parliament Square, London. Mr Horner was attacked as he tried to leave, the court heard

Police helicopter footage shows a fire that was lit by protesters during the December 2010 protests

Judge Jeffrey Pegden said he had 'absolutely no doubt' that policing the protests was 'frightening, stressful and exhausting'.

But that Mr Horner, who was not in court for the sentencing, 'simply wanted to go home' and had not committed an offence when he was attacked. No further action was taken against Mr Horner.

The judge told Ott he had carried out 'gratuitous and unnecessary violence' and abused his 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 Judge Jeffrey Pegden

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.'

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

'Your honour may feel think on that day he was pushed into losing his normally sound judgment in what was a long, tiring and terrifying day,' Mr Baumber said.

'It was a day that was traumatic. It was a trauma that still lives with him.'

Ott, who has served in the police 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', he added.

Ott sobbed in the dock as he was sentenced to eight months in jail today after being found guilty yesterday of one count of assault occasioning actual bodily harm.

He was cleared of perverting the course of justice.

Ott's colleagues, Pc Calvin Lindsay and Pc Thomas Barnes, were both cleared yesterday of perverting the course of justice.

PC Calvin Lindsay (left), and PC Thomas Barnes (right), 31, were cleared of preventing the course of justice

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

Deputy Assistant Commissioner Fiona Taylor, of the Met Police'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.'