Sorry, do you mean the lighting of fires on the roofs?
My best pal (a victim of the Blitz) always says they simply lighted lamps during the blackouts. Since he’s always pretty snide about my people, I tend to disbelieve him, lol.
They lit fires in the surrounding mountains to guide the Luftwaffe into Belfast.
http://markhumphrys.com/sfira.tyranny.html#ww2
http://blog.z-word.com/2009/01/gaza-jewish-legislator-in-ireland-compared-to-goebbels/