 The Military Corrective Training Centre—for all three services—at Colchester is operated by the Military Provost Staff Corps (MPS), an all-senior NCO corps which recruits only from serving personnel (but will liaise with other military and government sources where appropriate).MPS are not police and serve the same function as a prison officer.This role is additionally carried out by them on operations when handling foreign detainees at a main operating base such as Camp Bastion/Kandahar.