"Steve Firth" wrote in message
. ..
"nightjar" cpb@insert my surname here wrote:

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.

Hmm, which road in Camden Town do you think you could land a helicopter
on?

I don't know the area, but my local Police helicopter pilot reckoned he
could land his Twin Squirrel in an area about 15m wide and 25 m long. if he
really had to. Like most Police helicopter pilots, he was ex-military.

Colin Bignell