Corporal punishment, punishment by solitary confinement in a dark cell, and other cruel, inhuman or degrading treatment may be used as punishments for disciplinary offences. Punishment by close confinement or reduction of diet, by stripping in cold weather, and the use of instruments of restraint, such as handcuffs, chains, irons and straitjackets, are often a part of the penitentiary environment for both common criminals and political prisoners. Prison mistreatment may also include insults, mockery and non-delivery of letters.
Systematic torture and other cruel treatment is inflicted in many countries. Detention incommunicado and detention without trial for long periods create a maximum risk of ill-treatment and torture, as basic procedural rights and avenues of redress appear to be denied to persons thus detained. Disregard of the human rights of detained persons occurs most frequently under states of siege, emergency or exception. Furthermore, even where no state of siege or emergency is officially proclaimed, situations of social and political unrest and civil strife often lead to gross violations of the rights of detainees. They are alleged to occur particularly as regards government repression of national liberation movements, in countries under foreign occupation and in certain situations involving minority groups.
Prison officers are able to use their freedom of action to harass particular prisoners. This may range from surreptitious beatings, arbitrary deprivation of privileges to acts of humiliation such as urinating in the food or beds of prisoners in solitary confinement. Any protest, if possible, is treated as suspect and used against the prisoner.