In another city I was a part of they had a fully staffed courthouse with lawyers, a DA, detectives and all sorts of stuff. Some of my ideas are borrowed from them and some are my own views on where things fell down a little. I believe that RP should imitate life but you shouldnt need a degree in law to actually practice law. However, I think there are a number of really great basic things you may be able to implement with the right people to create some really nice law/PD RP interactions.
Please note that these are just suggestions, not demands!
Here we go - this may be a long post!
Players will whitelist for the role of "lawyer", they will get a law license in the same manner as all of the other licenses as it is in the city currently. They can have other roles at the same time (PD/NHS/... etc). If a person holds this licence and is found guilty of a crime they can risk having their license revoked and being disbarred. This means that criminals can no longer represent their friends but mob lawyers can still be a thing.
PD side - Population dependent it may be worth having some sort of District Attorney/Crown Prosecution Service representative where available within the Police station for processing criminals when they come in. This could be another PD (but preferably not in PD uniform for this interaction) doing it as an additional duty alongside their normal PD duties. Ideally this person would be in a suit and tie rather than PD fatigues. They would not have been one of the arresting officers on scene during the interaction. This is integral. The "lawyers" described above could fulfil this role.
Public Defender/Lawyer - the accused has the right to request legal counsel at the time of booking in. If they ask for this person then either A) a lawyer of their choosing or B) a public defender can be appointed to them. If a public defender is appointed this person could be anyone currently in the city who is qualified as a lawyer as described above. Likewise if there are 2 CPS/DA staff one of these could be assigned as the public defender.
billing could work as normal between players, or the public defender could offer to work "pro bono" for free effectively, if the RP situation is good then they could forego their fee and maybe claim it from the government/state or have some other way of getting the cash. The salary for this role should reflect the fluctuating demand and should provide enough money to be inline with other legal roles but not overshadow them. We dont want everyone being lawyers when NHS staff are in most demand!
Effectively at the point of arrest there would now be at minimum 2 players interacting (PD and accused) but could now involve up to four in the interaction (legal representation for both sides). You wouldnt necessarily want to lawyer up for a routine traffic stop but you might need to for a crime such as attempted murder?
I would assume (as i have little experience of the legal system at RPUK currently) that the current judge/jury and executioner is the arresting officer - these small changes could throw some additional parties into that mix with hopefully little effort and provide a more balanced experience for all. A fresh set of eyes on a case would help to ensure that the punishment fits the crime and lets the criminal know they got a fair "trial" rather than just a PD who throws the book at them for being a dick on the streets. Ive seen this happen in other cities where police got given god powers and some people let that power go to their heads. In my limited PD interactions here it doesnt seem that way but there will always be people who moan i realise.
I assume PD have a uniform change spot as part of their "go on duty" procedure so having a suit and tie "uniform" at this location would be pretty ace to switch between the two roles. It might also provide the PD guys with a little bonus income if they took the bar exam!