I get that pomp and circumstance is important for Brits to not become depressed, but doesn’t it become meaningless if a normal cop with his bullet proof vest and radios and cargo pants, is standing right next to your ceremonial cop who’s supposed to represent eternal tradition?
the red jacket guys with funny hats are there to protect against metaphysical threats, the anglo history of imperialism, ethnic cleansing, and death come with the consequence of a lot of very angry dead people. the outlandish hat and jacket serve to ward off and confuse rightfully vengeful spirits, who think they must be in another country with all these tall people with colorful clothes about (British people are short from malnutrition, and would never wear a color without ulterior motives), and the mounted bayonet on the rifle is actually the primary spiritual weapon (guns cannot be used in astral combat, you must use a weapon that physically connects you and your target); the rifle is only there to present an air of modernity and mundanity to the civilians and tourists. they maintain a constant ritual/magic circle around the palace with their rigid robotic routines - routines they cannot, ever, disregard without consequences, even should an innocent child be in the way.
the normal cops are just cops