§ Mr. Mullin
To ask the Secretary of State for the Home Department if he will list the prisons in which prisoners are confined to cells for 22 hours a day or more; how many prisoners in each prison are so confined; and what the reasons are. 
§ Mr. George Howarth
The Prison Service does not collect centrally information on the time individual prisoners spend confined to their cell.
Provisional data show that, for the year 1998–99, the average time prisoners were locked in their cells was 13.4 hours on a weekday and 14.7 hours at weekends.
Within a prison establishment, the period for which individual prisoners or groups of prisoners are unlocked will vary according to a number of factors, including their level on the incentives and earned privileges scheme. Some prisoners may be confined to their cells for most of the day, though usually only for short periods. Reasons for this might include for the maintenance of good order and discipline, because the individual prisoner has declined regime activity or because of operational demands.