Many prisoners do have access to TV. As far as I know BBC1,BBC2,ITV,Ch4,Ch5 only. I don’t believe there is any censorship – some inmates have TV’s in their cells.
I’d have thought with the internet most inmates can look up the details of their colleagues’ trials. Perhaps not directly, but via visitors etc. You surely can’t expect your identity to remain a secret?
Just to be clear – prisoners do not have access to the internet*. Before the internet, there were still ways for visitors etc to share what another inmate had been convicted for.
(* I’m not sure if long term prisoners in low security / open facilities before they get released get access to the internet to help them acclimatise to the outside world. Imagine the culture shock if you were banged up in the 90’s and then suddenly you are released. However certainly within “normal” prison you don’t get the internet.).