Bosses at security firm G4S, which runs HMP Oakwood in South Staffordshire, have put contingency plans in force as a rooftop protest continues at the prison.
A spokesman confirmed six prisoners were involved in the incident.
We can confirm that an incident involving six prisoners is taking place at HMP Oakwood.
The Ministry of Justice has been alerted and our normal contingency plans have been enacted.
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Apart from a few showers, mainly in the morning, there will be a good deal of dry and bright weather.
Any cloud and rain will clear eastwards initially, leaving brighter conditions but also a scattering of showers through the day.
Rain possibly heavy at times. Relatively mild overnight.