In the United Kingdom, Indeterminate Public Protection prison sentences (also known as Imprisonment for Public Protection or an IPP) are a form of indeterminate sentence.[1][2] They are intended to protect the public against criminals regarded as too dangerous to be released when the term of their original sentence has finished.
The equivalent for under-18s is called detention for public protection.
These are for defendants whose crimes are not serious enough to merit a normal life sentence, but who are a danger to the public and so should not be released until the Parole Board decides they no longer represent a risk.
Although it is possible that some prisoners detained under IPPs may never be released, the possibility of their being released on review exists, and these sentences should not be confused with a sentence of life imprisonment with a whole-life tariff.