A research study into prisoners received into prisons in England and Wales under Indeterminate Sentences for Public Protection (IPP) between April 2005 and March 2006, showed that (a) 13 offenders were given an IPP for sexual assault, (b) 14 offenders were given an IPP for sexual assault of a child under 13, (c) 14 offenders were given an IPP for sexual activity with a child and (d) 44 offenders were given an IPP for arson. These figures were published in chapter 11 of Offender Management Caseload Statistics 2005, a copy of which can be found in the House of Commons Library.
These figures have been drawn from administrative IT systems and data returns from prison establishments which, as with any large scale recording system, are subject to possible errors with data entry and processing.