Not a single security type person to be seen anywhere. I'm sure I was followed by MI5, but they were very discrete. Once I got to Buckingham Palace, I saw armed police, soldiers, cavalry etc. I thought it was unusual active duty US Air Force stayed on the same floor at the hotel in London. They checked in just after I arrived. But on the trains, subway, buses, no type of security.
Cameras were everywhere. They call it CCTV. Everything has changed since I lived there. I never ever saw armed UK police back in the 70's. All the US bases are fenced off, they used to be fairly open during the Cold War.
I saw so many beautiful women, I didn't want to come back to Colorado. Maybe it was because I was in the high end of the city. There were many expensive exotic cars parked in the neighborhood. It seemed like rich folks from all over the world lived there. It was very crowded and noisy. The price of a small apartment averaged $600,000. I would have to live out in the country with the economy in London the way it is now. I didn't hear of anybody being shot the whole time I was there. There was a shooting of a terrorist in London the week before I got there tho'...
https://en.wikipedia.org/wiki/2020_Streatham_stabbing