A YOUNG inmate knocked out an unsuspecting prison officer with a single blow, during a surprise assault at a young offenders’ institution.

Angus William Hollingsworth was said to be “bouncing” when other officers arrived following the exercise yard attack at Deerbolt Young Offenders Institution (YOI), near Barnard Castle.

Durham Crown Court heard his demeanour was of someone under the influence of drink or drugs.

Penny Bottomley, prosecuting, said when asked why he did it, 19-year-old Hollingsworth told other officers: “Yes, I did it. He’s had it coming to for ages.”

She said the blow was so forceful that Hollingsworth’s hand required medical treatment.

The injured officer came round after initially falling unconscious, and suffered cuts to his mouth, plus cuts and grazes to his back and elbow.

Miss Bottomley said he suffered anxiety, stress and dizziness several days after the attack, and, on a much longer basis endured almost daily headaches, some lasting two to three days.

The court heard the officer has been in the Prison Service for 26 years and this was the first time he has been assaulted.

Following a period of sick leave, he decided to return to work, although he was now much more cautious.

Miss Bottomley said at one point there was a suggestion another inmate may also have taken part in the attack.

But, at a plea hearing last month, Hollingsworth admitted assault causing actual bodily harm, on the basis that he hit the officer a single blow and that no-one else was involved.

The court was told it happened as the officer was overseeing Hollingsworth and three other inmates in the exercise yard on February 28.

He had no recollection of the incident, but must have pressed his emergency alarm, as other officers were alerted and reached the yard promptly.

Hollingsworth, formerly of Annfield Plain, near Stanley, was serving an 18-month sentence for a knife-carrying incident during which he made threats, in 2013.

Marian Cleghorn, mitigating, said Hollingsworth, now 20, is at risk of becoming “institutionalised”, but is starting to conform to life behind bars and has found a skill in woodwork that he would like to pursue as a potential job on release.

She added he would like to apologise to the officer for the attack and injuries caused.

Adding an extra 15-months to Hollingsworth’s sentence, Judge Simon Hickey described it as a, “planned and deliberate offence”.