Two inmates already serving life for murder have been sentenced to six more years each for threatening to kill a prison officer days after the murder of Fusilier Lee Rigby.
Feroz Khan and Fuad Awale, both 26, were found guilty at the Old Bailey last week following the incident at HMP Full Sutton in North Yorkshire on May 26 last year.
Khan was also convicted of inflicting grievous bodily harm on prison officer Richard Thompson after relations between Muslim inmates and guards ''became strained'' in the days following Fusilier Rigby's death.
Judge Michael Topolski QC today sentenced Khan to six years for threats to kill and three years for GBH, to run concurrently at the end of his life sentence with a minimum of 20 years.
Awale was also sentenced to six years for threats to kill, to be served at the end of his life sentence, which carries a minimum term of 38 years.
Passing sentence, the judge said: "This was a premeditated, well planned and carefully orchestrated attack on a single and previously identified prison officer, who was, as such, performing a public duty and upon whom it has had a significant impact.
"The events as a whole formed part of a joint enterprise involving force and weapons, committed by men with convictions for murder.
"Both of you carried weapons to the cleaning office.
"Given the context, the level of threats uttered and repeated were truly appalling, causing great anguish, not just to prison officer Thompson but also his colleagues who were convinced he was going to die in horrific circumstances."
The men were cleared by the jury of charges of false imprisonment during the four and a half hour stand-off along with co-defendant David Watson, 27.
Khan was also found not guilty of assault occasioning actual bodily harm against another officer.
Their trial earlier this year heard allegations that t he defendants called for the release of Abu Qatada and Roshonara Choudhry, a student who attempted to stab MP Stephen Timms to death in 2010.
They were also accused of demanding to be flown to Afghanistan, the jury heard.
Awale had taken knives from a cleaning office cupboard and rubbed them together giving the impression he was "preparing to carve a Sunday joint", the judge said.
He told Mr Thompson: "Stop struggling - I've killed two people, I will kill you, I will kill you."
The officer said he had "every belief" he would be killed if he did not do as ordered because of the "intensity and seriousness" Awale had displayed.
Awale at one point asked Khan "can I give him one in a non-vital area?" and later said: "I thought his head would have come off by now."
Khan, for his part, told Mr Thompson that he had more reason to be fearful because he was believed to be ex-military, the court heard.
When he denied having been in the military, Khan told the officer: "Well, somebody has to make a sacrifice."
Judge Topolski told Khan that the incident had been his plan, that he had recruited the others and was "the leading voice speaking on their behalf".
Awale had also played a "very significant role", threatening Mr Thompson more than once and convincing him he was going to die, the judge said.
"I have decided that in relation to your convictions for threats to kill, you and Khan are differently but equally culpable," he added.
Paul Hynes QC, defending Khan, said his client had hit Mr Thompson "harder than he meant to and harder than was necessary, by his own admission".
But he claimed that, based on the jury's decision to acquit him of the charge of false imprisonment, it could be said that his client's actions amounted to a case of "excessive self-defence".
Mitigating for Awale, Joel Bennathan QC said that it had been shown that there was no "terrorist motive" behind the attack, and that the men had made their demands "for effect" rather than as an "act of jihad".
The barrister said his client had been in "real fear for his life" following the murder of Fusilier Rigby on May 22.
"He had suffered multiple attacks himself in prison, and from his perspective at least, the prison seemed unable to protect him," Mr Bennathan said.