I think some of the context is missing here.
Yes the Tories started to implement an early release of prisoners, but this has now been intensified by the current Labour Party directive to crack down quickly and sharply on anyone prosecuted for violence during the riots.
These people (mainly men) should of course be prosecuted if identified for committing violence, intimidation, racial abuse or whatever. But what has happened is that (political influence of the system) has meant these prosecutions are being expressed through the courts at a rate that is unprecedented.
ie as one commentator said, because Labour wants to signal how wrong they think these people are (and yes the probably are) the courts are being asked to as it were be seen to / ie perform justice at the expense of those already waiting trial, and the log jam in prisons.
Not quite sure why if Labour wants to be seen as cracking down on rioters, that they dont open up again those abandoned military bases, or even the infamous barge, to house them as they have been for asylum seekers.
So this political posture by Labour for justice for rioters to be seen to be quick and punitive has just added to existing problems
https://commonslibrary.parliament.uk/will-prisons-run-out-of-space/