A PRISON officer's career is in ruins after what a judge described as "a vicious, unnecessary, unprovoked and gratuitous attack" on a teenage inmate.

Michael Ambrose will lose the job he has had for 18 years and probably a pension lump sum for the assault at Deerbolt Young Offenders' Institution, in Barnard Castle, County Durham.

Ambrose twice kicked and once stamped on the 18-year-old then tried to hide his involvement by encouraging a more junior officer to edit what had been caught on CCTV.

The 44-year-old father-of-two, from Hetton-le-Hole, County Durham, admitted a charge of assault by beating at the 11th hour as he was due to go on trial at Teesside Crown Court.

The judge, Recorder Elliott, QC, who said he could easily have broken the inmate's legs, imposed a three-month prison sentence, suspended for two years, with 100 hours of unpaid community work.

He told 6ft 3ins Ambrose: "You have paid, in your mid-40s, a very very high price for what happened, and you have brought shame on yourself, but also on your family and your work colleagues.

"This was a disgraceful episode, and you should be thoroughly ashamed of yourself.

"You have clearly had a loss of control, and what followed was a vicious, unnecessary, unprovoked and gratuitous attack on a defenceless young man, prone on the ground."

Camera footage of the brutality was shown to the court, and happened when the inmate was being moved from one wing to another on August 1 last year.

The teenager's mother – who battled for an investigation despite the altered discs not showing Ambrose involved – sobbed and gasped in the public gallery as the recording was played.

Prosecutor Shaun Dryden told the court that the inmate was described by another officer as "fairly pleasant and chatty" a she carried out his transfer.

The teenager then tried to use a telephone and was told off, before being taken into an office where a melee started and he was restrained in the ground.

Ambrose pushed past two colleagues and delivered his kicks and stamp, said Mr Dryden, leaving his victim with bruised legs.

Rosalind Scott Bell, mitigating, said: "I would like [the teenager's] mother and indeed the court to know, that by the defendant pleading guilty today and Mr Ambrose accepting his guilt, he has asked me to extend his apology to her and her son, and to the Prison Service.

"He has led, thus far, a good and industrious life. He has put all of that in peril, and he will lose his job because of this.

"He is sorry and he is remorseful, not just for the predicament he finds himself in, but because he lost his self-control on that day. It was something he had held and was able to control for 17-odd years.

"It is a matter that was totally and utterly out of character. He has now lost his good character and he has lost his employment, and will have to start all over again. It has been a long fall."

Mrs Scott Bell said Ambrose had a difficult and stressful job as an officer, and also trained other members of staff, and was highly regarded.

One of three references given to the court described him as "always acting with integrity and care, with appropriate fairness".