IPPs were introduced by Labour as a means to try to deal with a small number of potentially dangerous repeat offenders- by introducing an indeterminate licence period Probation could manage such people and their risks including recall to prison without having to take them back through court or potentially them reoffending.
however, in practice it went tits up and the courts handed them out like smarties to somewhat complicated but small beer offenders like the poor soul in the article. They should never have been used for stealing phones etc but they were given out with ridiculously short tariffs like 2 years, 18 months etc. The problem these unsuitable for IPP guys and girls then faced is that few prisons had the offence related programmes for them to complete in order for the Parole board to agree their licence conditions and release from prison. So most got stuck.
About 4000 or so are now persistently affected by the IPP sentence despite it being struck out in 2012. Some are admittedly people who would have gone on to be on life licence, but most were place on it inappropriately and are stuck. It should have been dealt with in 2012. It is a human rights abuse. I have worked in prison mental health and work in secure mental health and yes it does have huge and lasting impacts - the hopelessness of the situation which is never ending in the current horror of the prison estate in England and Wales, where the regime in many jails has not been restored post Covid (23 hour lock up), they are filthy, no repairs, full of vermin, short staffed, etc. and when they see people released at tariff or on parole for the same crime or much worse, it drives many of the suicides of IPP prisoners.
I would say it is not so much corruption preventing this from being dealt with, rather an inept government where ministers are never in post long enough to be on top of their brief and are terrified of the right wing press that they think represents the voter to actually get to grips with such a thorny problem. Whereas I think there are a couple of fairly straightforward solutions that could be implemented by a minister with a brain and backbone!