In the United Kingdom, policing is provided through 64 constabularies throughout 12 regions, and a number of national, non-geographic forces. Police are empowered by law to investigate crime and bring criminal charges. After a charge is brought, the case is prepared for trial by the Crown Prosecution Service.
Police officers in Britain are ranked from Constable to Commissioner, with a parallel rank system for Detectives. Special Constables are unpaid, volunteer officers who perform police duties in their spare time. Since 2003, Police Community Support Officers (PCSOs) have been introduced who patrol and investigate, but are not given the same powers of arrest, stop and search (except for discreationary powers which vary by constabulary), or physical intervention as full officers. PCSOs have a shorter term of training - only 8 weeks compared to 24 weeks for a P.C.
The Police are primarily governed by the Police and Criminal Evidence Act 1984 which sets out the powers and responsibilities of officers, including those related to stop and search, search of properties and vehicles with a warrant, arrest, interview, detention and record-keeping. Extra rights are given to the Police under the Terrorism Act 2000 and an number of other laws which enable them to investigate terrorism, as well as the laws related to breach of the peace, public order and anti-social behavior.