The sentence of Imprisonment for Public Protection must count as one of the least carefully planned and implemented pieces of legislation in the history of British sentencing. Projections about levels of use were totally inadequate and, as a consequence, the resources required to implement the sentence were far too limited. Behind these practical problems lie more fundamental questions about the ability to predict the risks posed by those convicted of violent and sexual offences – and to predict reductions in risk. If the ability to predict risk has been overestimated – as we believe – then the basic rationale of the sentence may be open to question.
The Brian Barder blog has much more on this subject - please take a look. The Guardian 8th July 2010 highlights the problems inherent in IPP and another article by Joshua Rozenberg contains trenchant criticism of this form of sentence. There is really no sensible alternative but to abolish IPP.