What is Immigration Detention?
There are currently 10 IRCs across the UK [See source]. Immigration detention centres are closed, prison-like establishments. People can be held indefinitely and there is no automatic judicial oversight on decisions to detain. Detainees are not serving any criminal sentence. The decision to detain is made by an official of the Home Office and the purpose is administrative (i.e. to make processing their asylum claim easier, of to make removing them easier). It is not ordered by any court.
There is no time limit on detention and detainees do not serve a specific term. They can be released at any time, or stay for years. The majority of detainees are detained for less than 3 months, but there is a significant number who stay longer than 12 months.
Large-scale immigration detention is a relatively recent phenomenon and is on the rise: Approximately 30,000 people are now detained each year compared to only about 200 in 1987 and only 50 in 1988.