Prison sources have said the movement of over 30 inmates from Maghaberry to the lower-security Magilligan jail over the last week is an attempt to ease tensions at the troubled prison.

While prisoners reaching the end of their sentence, or serving terms for less serious crimes, can be transferred to the Co Derry jail it is unusual to have such a large movement at one time.

The high-security Maghaberry prison has been subject to a number of highly critical inspection reports.

New management brought in to try to reform the prison have had only limited success to date, with staff saying morale is at an all-time low.

The murder of prison officer Adrian Ismay in March by the dissident group calling itself the 'IRA' has further increased tensions in Maghaberry where republican prisoners are held on a segregated landing.

One man, Christopher Robinson from west Belfast, has been charged in connection with the murder. He was released this week on bail, with strict conditions.

Since the murder prison sources have said there has been an increase in staff sick leave, placing additional pressure on the jail which was already running on limited resources.

Prolonged periods of prisoners being locked in their cells due to staff shortage has created an atmosphere sources have described as 'toxic'.

There are currently around 860 inmates housed in Maghaberry near Lisburn, with around 460 in the medium-security Magilligan.

The movement of prisoners between the jails is understood to be an attempt to ease tensions.

Maghaberry houses both remand and sentenced adult male inmates as well as loyalist and republican prisoners.

Chief Inspectorate of Prisons in England and Wales Nick Hardwick last year described it as "the most dangerous prison I've been into throughout my time as Chief Inspector"

A follow-up report, the findings of which were published in February of this year, found that the prison had stabilised but remained unsafe for both inmates and staff.

Asked about the movement of inmates, the Prison Service said it does not comment on operational matters.