Inmates at Cloverhill Prison were in their cells for an extra hour this afternoon because of a row over staffing levels.

It is the first of several planned work stoppages by prison officers in two of the biggest jails in the country.

Prisoners are usually locked in their cells for one hour at lunchtime every day, but today their cells remained shut until 3pm.

Workers have accused the Prison Service of breaking promises in relation to staffing levels, which they claim are dangerously low.

The Prison Officers Association says their members can no longer be expected to deliver the same full service if they are not given the required staff.

The Irish Prison Service claims workers are in breach of the Haddington Road Agreement, which prevents them from engaging in strikes or other forms of industrial action.

Talks aimed at preventing the stoppages have taken place behind closed doors - but prisoners will be left in their cells for an extra hour again tomorrow if this dispute is not resolved.

Officers at Mountjoy Prison are planning to stage a similar stoppage for two days next week.