A VIOLENT armed robber involved in a vicious prison beating will serve extra time behind bars after judges condemned him as a time-waster.

Rais Cameron Atcha, 27, was already doing a 12-year stretch for a robbery conspiracy at HMP Garth, in Leyland, Lancashire, when he exploded into violence.

He repeatedly kicked, punched and stamped on a fellow inmate during a gang attack in October 2014.

Atcha, from Bolton, was handed two and a half years jail after pleading guilty to assault occasioning actual bodily harm at Preston Crown Court in July.

Today he made a doomed bid to convince top judges at London's Criminal Appeal Court that his punishment was too tough.

He claimed he was treated too harshly in comparison to the other three men involved in the prison attack.

But his challenge was thrown out - and Atcha had an extra 28 days tacked onto his sentence for wasting the courts' time.

The court heard the "vulnerable prisoner" was pursued by Atcha and three others, and knocked to the floor.

He was punched, kicked and stamped upon by Atcha and slashed with improvised bladed weapons by two of the others.

The beating was caught on CCTV and Mr Justice Goss said that Atcha had "initiated the chase and delivered the first blow".

Atcha complained it was unfair that his sentence for the attack had been ordered to run consecutively to the term he was already serving for robbery.

He pointed out that his co-accused had been given concurrent sentences.

But the judge, sitting with Judge Jeremy Carey, dismissed his complaints as "totally unmeritorious."

Describing his grounds of appeal as "wholly speculative," he added: "This man should not avoid punishment for this serious offence."

He went on to order that 28 days Atcha has already served should not be counted when calculating his release date.