At a national level, the clearance rate for murders is ~61% per https://ucr.fbi.gov/crime-in-the-u.s/2019/crime-in-the-u.s.-... . Property crimes are <20%.
The FBI's UCR Data Explorer used to give you an easy to use breakdown of crimes and clearance rate at the national/state/metro/city level, but unfortunately they redesigned it and now it is both harder to use and presents less data. I guess that is one way to hide data that isn't favorable? There seems to be more emphasis on the danger presented to law enforcement officers, but the #1 cause of death for officers by a large margin, per https://www.odmp.org/search/year?year=2021, has been COVID.
I wonder if a large contributor to the higher London clearance rate is related to socioeconomic factors or surveillance laws/systems.