A jury has found two prisoners guilty of inflicting grievous bodily harm with intent on another inmate at Westgate Correctional Facility.

After two hours of deliberation, the jury delivered a unanimous verdict on both Kenneth Burgess and Kamel Trott. The attack on Dennis Robinson left him with several injuries including a broken jaw, perforated right ear and fractured eye socket.

The pair will be sentenced at Supreme Court on Monday, after the prosecution have submitted a Victim Impact Statement on behalf of Robinson.

Robinson, 38, and Burgess, 36, were jointly convicted of murdering the twins Jahmal and Jahmil Cooper in a trial two years ago. The prosecution said Burgess attacked Robinson in retaliation, blaming him for his conviction.

Trott, 32, joined in the attack, just days before he was due to be released from a three-year sentence for unlawful wounding with intent in a separate incident.

The pair attacked Robinson in his cell on June 6, 2007, during a recreation break when the noise level inside the prison was akin to that of a "football match". Robinson said after the assault, the pair pulled a table up outside his cell and sat there playing cards, to intimidate him from coming out of his cell.

A prison guard discovered the injured Robinson as he made his lockup rounds after the break. He spent the next three weeks being treated for his injuries in hospital.

During the two-week trial, Robinson said Burgess threatened to kill him during the assault, telling him to write an affidavit exonerating him of blame in the Cooper twins' case ahead of his appeal. He said Burgess also threatened to harm his three-year-old daughter, warning him Trott was due to be released in a few days' time.

However, defence lawyer Elizabeth Christopher said rather than Burgess having a grudge against Robinson, it was the other way round. She said the white T-shirt bearing splatters of Robinson's blood found in Burgess's cell did not belong to him but had been "planted" by another inmate.

Richard Horseman, defending Trott, claimed the cells were not secured properly ahead of the Police gathering evidence a few days later, and therefore that evidence was "compromised".

He said Robinson was trying to blame Trott because he had told other prisoners he had seen him performing oral sex on another inmate two years previously, and that "Robinson was a woman".

However, Robinson denied the rumour at the trial and the prosecution said it was unlikely he would wait two years to take action against Trott.

Rory Field, Director of Public Prosecutions, said during the attack the cheekbones to the left of Robinson's face were "essentially pulverised" from repeated blows.

Mr. Field said Burgess and Trott "wouldn't have necessarily thought they would have been complained about, and that it would have been taken to such a degree by the authorities".

He said neither had an alibi. DNA evidence also linked blood splatters on a t-shirt in Burgess's cell and on a vest and t-shirt of Trott's to Robinson.

The pair will be sentenced at 2.30 p.m. on Monday.