On my first trip to America as a child (a long time ago when there were very few armed police in the UK).
I saw my first armed police officer called onto a Greyhound bus.
An unruly passenger was being removed.
The cop had no compunction in pulling out his weapon and pointing it at the passenger.
That was pretty scary for me (maybe more than for the perp).
I doubt any Heathrow cops would point their weapon at a drunk.
Weapons now just form a visual part of the dehumanising mass of equipment police always carry and it barely registers with me any more.