The UK's only prison ship will close in two weeks, the prison service says.
The vessel off the Dorset coast held 400 inmates
HMP Weare, berthed at Portland, Dorset, was described as "merely an expensive container" by chief inspector of prisons Anne Owers last year.
Prisoners are being transferred to other jails, but it is not yet clear what will happen to the vessel itself.
Prison officers have welcomed the decision to close the ship, but criticised the short notice they have been given.
"By August 12 prisoners will have been released or transferred to other prisons and staff are being redeployed to other prisons," the statement read.
"No prisoners have been released early and no compulsory staff redundancies are anticipated."
Weare, originally a troop ship in the Falklands war and then a floating jail in the US, had been heavily criticised in prison service reports.
Tim Hogg, a prison officer at the Weare and branch secretary of the Prison Officers Association, said today: "It's obviously been well overdue in coming.
"We are pleased the date has now been decided but with it being such short notice, staff will be in even more turmoil than before.
"August 12 is only two weeks away so staff have only two weeks to report to their new jail so won't have time to find accommodation and settle their families."