Many jails have more prisoners than their target limit, but meet a level considered safe. According to this definition, prisons have been overcrowded every year since 1994.

Since 1997, more than 17,000 extra prison spaces have been created. A further 8,000 are planned, but critics say this may not be enough.

In early 2007, some prisoners were being held in court and police cells because jails were full.