In message , nightjar
writes

"Brimstone" wrote in message
...

Possibly they're markers for police and other emergency helicopters?

That sounds the most likely. They would want to know where the posts are
when trying to land on a road.

You'd never land a helicopter on the road concerned. The south circular
in these parts is a narrow single-carriageway road, with buildings right
up to the pavement.

Also, most buildings are higher than the lamp posts - I can clearly see
the upward-pointing blue lights from my second floor because they are
just below window level. They are very hard to see from pavement level.

I wondered if they could be for aircraft recognition because we are
close to the spot where the Battersea heliport flight paths cross the
incoming Heathrow flight path, albeit at a lower level. But if these
lights are appearing in other parts of London, that would not be the
reason and, as has been pointed out, there is plenty of light diffusion
on main roads to see their positions from the air.

Given that the blue light is in the position normally occupied by the
dusk - dawn light sensor, I wonder if the blue glow is some way of
making the sensor more accurate in densely-lit areas?
--
Paul Terry