No prisoners have cell keys in their possession. In 32 Category C prisons, six semi-open prisons and five closed young offender institutions (YOIs), cells are fitted with privacy locks which enable prisoners to open and close their cells only during periods when the cell locks have been unlocked by staff. Privacy locks do not enable prisoners to leave their cells unless unlocked by staff, nor do they enable them to prevent staff from entering. Open prisons and open YOIs do not normally have cell locks on individual cells.