The Essence of Yellow Fluorescence

My summer hols this year have consisted of ceiling-bathing so far. It's not bad, when the phone doesn't ring and the housework's done.

I saw a funny thing today. I was driving past a shop that sells workwear- fluorescent vests, chefs aprons, donkey jackets and so on.
Across the dual carriageway were about 15 policepersons, all in yellow fluorescent vests ('Police').
A small squad of under-tens were wobbling round the street corner on their bicycles, indicating left with timidly semi-outstretched arms, all dressed in yellow fluorescent vests ('Harrow Safety School').
And on the other side of the road was the refuse squad, in yellow fluorescent vests ('Refuse').
It was as though they'd all just popped to the shop in at the same time, put their vests on at once, and left to get on with the job.

Finally, I took this photo months ago at Barnet Police Station's Open Day. It was right in the middle of one of the Met's many race rows.