It's a lovely idea, but Peelian principles are currently only paid lip-service. People are trying to drag it back to something approaching that, but it's not the current actual situation, particularly in London. (Kettling, etc.)
> are operationally independent of HM government,
> the police literally are not the government,
> do not spy for the government,
Again, in the sense of "political party currently in control of Parliament", yes. But they're literally the enforcers of the law -- and their meaning of the law. People not in Parliamentary systems have a broader, and far more useful meaning of "government" -- those governing, determining what is going to be punished and what won't. If you're actually stuck on term "government" in the partisan meaning, please give me some other term to refer to the coherent actions of the state. The bureaucracy and enforcement arms actually do govern, regardless of whether they're doing so at the behest of particular partisan guidance (though sure, that's worse in terms of being able to politically course correct). An arrest and detention whilst CPS sorts out taking to the next level is actually a punishment. Hence the quote "You can beat the rap, but you can't beat the ride."
> do not routinely surveil the population; their surveillance powers are limited and regulated.
Hah. Hah. Hah. https://www.nytimes.com/2020/01/24/business/london-police-fa... .