The Criminal Justice and Immigration Act 2008 (c 4) is an Act of the Parliament of the United Kingdom which makes significant changes in many areas of the criminal justice system in England and Wales and, to a lesser extent, in Scotland and Northern Ireland. In particular, it changes the law relating to custodial sentences and the early release of prisoners to reduce prison overcrowding, which reached crisis levels in 2008. It also reduces the right of prison officers to take industrial action, and changed the law on the deportation of foreign criminals. It received royal assent on 8 May 2008, but most of its provisions came into force on various later dates. Many sections came into force on 14 July 2008.