Prisoners are automatically on standard privileges at the start of a sentence. They can be upgraded to enhanced privileges or reduced to basic privileges for bad behaviour.
Individual prisons each have their own set of rules. But generally speaking, on basic, you’re not allowed anything other than the law requires.
So no opportunity to rent a TV.
No wearing own clothes.
No canteen ( spending your own money in the prison shop )
No letter writing or visits, other than the minimum the law says every prisoner is entitled to.
No gym or association ( may not be applicable to a cat A prisoner anyway. Not sure about that. )
Various other things that may seem trivial in the extreme when you’re talking about a multiple baby murderer. But are things that someone with nothing to lose in terms of an increased sentence, will most likely take as a serious deterrent against poor behaviour.
Reading it back, quite a few of these things, like wearing own clothes for one, probably don’t apply to cat. A prisoners anyway. I was just talking generally about prison regime.