The Imprisonment for Public Protection (IPP) sentence was introduced by the Criminal Justice Act 2003, came into force in April 2005, was substantially modified in 2008, and abolished in December 2012.
They were introduced to enable sentencing courts to impose an indeterminate sentence (one with no automatic release date with release only available when the Parole Board is satisfied that the offender is safe to be released) on an offender who was considered to be dangerous but whose offence was not serious enough to meet the requirements for a life sentence to be imposed.
A minimum term was imposed by the sentencing judge and that had to be served in full before the Parole Board could consider release. If an IPP prisoner is released from prison, they are liable to remain on licence for the rest of their lives (meaning that they can be returned to prison if they breach their licence conditions or commit any further offences) although IPP prisoners subject to life licence can apply to have their licence cancelled 10 years after they have been released from prison.
The sentence proved controversial because it was imposed in a wider range of cases than Parliament had perhaps anticipated and there was inadequate provision of offending behaviour courses for prisoners who received an IPP sentence which meant many of them found it difficult to demonstrate to the Parole Board that they were safe to be released after they had served their minimum term.
A total of 8,711 IPP sentences were imposed and, on 31 December 2019, there were 2,134 people in prison still serving an IPP sentence who had never been released, with only 144 of them yet to complete their minimum term. A further 1,260 recipients of IPP sentences were also in prison on that date having been released but subsequently recalled to prison.