A prisoner at the Brook House Immigration Removal Centre near Gatwick, West Sussex, United Kingdom was found planting tattoos on fellow inmates using a contraption that he built himself from gear that's given to inmates for recreation.
The inmate stripped down a console of a Sony Playstation, attached a ballpoint pen to the motor and used it to drive ink into people's skin. While this is neither the most hygienic, nor the best ink to use, it nevertheless is the ultimate definition of a prison tattoo. The device has been seized and is being held by the prison.
SOURCE: The Sun