Six inmates received longer sentences following a disturbance at Whitemoor Prison in which up to 10 officers were injured as prisoners hurled snooker balls, tables and chairs at them.

All six were in the dock at Woolwich Crown Court this week and admitted charges of violent disorder.

The case took two years to get to court following the incident at the March top security prison on the night of March 30, 2017.

One report at the time said unrest continued into the following day with police dogs called in to retain order.

Some prisoners were removed as a result and sources inside the prison told one newspaper that the trouble erupted after an inmate with mental health issues was moved to a regular wing.

“It was a nasty and prolonged attack,” was how one source at the time summed it up.

The crown court hearing this week accepted that violence erupted after officers attempted to restrain an inmate who had refused to move to another part of the jail.

David Smith, 36, Marvis Smith, 33, and Robert Lainsbury, 25, tried to barge into the cell but failed and became violent.

Together with fellow inmates, Ruben Francis, 37, Kalil Robinson, 25, and Abdul Miah, 36, they threw snooker balls, tables and chairs at prison officers, with some suffering minor injuries.

The officers retreated and, after 15 minutes, the prisoners calmed down and started cleaning up the mess.

The men were sentenced at Woolwich Crown Court on May 1 after all pleaded guilty to violent disorder.

David Smith was jailed for two-and-a-half years, to run consecutively with his life sentence for murder; Marvis Smith was jailed for 12 months, to run consecutively with his 38-year sentence for murder and Francis was jailed for two years, to run consecutively with a sentence for robbery.

Lainsbury was jailed for 18 months, to run consecutively with his 26-year sentence for murder.

Robinson was jailed for two years, to run consecutively with his 14-year sentence for aggravated burglary, and Miah, who was released from prison before the case was heard, was jailed for six weeks.

DC Shelly Reeve said: “With the level of violence these men showed, the prison officers made the right call in getting themselves out of the wing.

“The men had already proved they were dangerous when they were sent to a category A prison, where the most serious offenders are kept.

“As a result of their actions, they will be staying there a little while longer.”

Last year’s findings of the independent monitoring board at Whitemoor concluded that whilst prisoners are in general treated fairly some areas are “affected disproportionately by regime restrictions and staff shortages”. The report singled out segregation, the close supervision centre, healthcare and reception as specific examples of where those shortages were affecting Whitemoor.

The report also concluded that more could be done to done to address the particular needs of the 23 per cent of inmates who are foreign nationals.

“The wide range of religious, ethnic and national groups requires further effort to promote mutual respect and understanding,” said the report.

It added: “The prison is generally well managed and offers prisoners an environment which is calmer and safer than that of many other establishments.

“The board have been pleased to note an increasing number of improvements. There do remain several areas of concern, some of which are the result of national policy, and are therefore outside the control of Whitemoor’s management.”