This portrait shows Jack Hambury in his bluette overalls. He was an air raid warden in London (possibly in the Brick Lane area in east London). Of note is the badge above his ARP badge. It looks like an area badge but is quite unique as it arches down at the corners rather than up. I attempted to magnify the badge but the resolution was not good enough to determine the area.
News about interesting insignia, ARP related info and period photos that turn up.