This interesting photograph appears to show a District Warden from Holborn in central London assisting a child with her 'Mickey Mouse' style gas mask. The most peculiar part of his uniform is the placement of the three bars of rank on the lower sleeve. I am assuming these are the yellow bars to denote a district (sometimes called divisional warden). They usually appear at the top of the sleeve. The warden's jacket is somewhat peculiar as well. I thought it was a standard issue battledress but this jacket has chrome buttons to cuff and epaulette - standard issue had revolving shank to epaulettes and a black plastic button to the cuff closure. The area title for Holborn is above the pocket (even above his first world war medal ribbon trio). I think the main badge is the ARP red on black breast badge but I cannot make it out for certain. He also does not have any shoulder titles. The helmet is a standard issue one for a district warden - a single black stripe. He is also wearing a Civil Defence armband which is against the usually prescribed use(they were to be worn over civilian clothes). All-in-all a most peculiar uniform.
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