R2I, RTI, or resistance to interrogation is a name for a set of techniques taught to elite UK troops, and other NATO soldiers with the express purpose of preparing them, after capture by the enemy, to resist interrogation techniques such as humiliation and torture. The trainees undergo practices such as hooding, sleep deprivation, time disorientation, prolonged nakedness, sexual humiliation and deprivation of warmth, water and food. Many of these techniques are against international law if used in interrogations.