The Girl Guides (and also the Brownies) were heavily involved in assisting with the war effort. From 1938 the group planned how it could assist in the event of war breaking out. During the war Girl Guides assisted at First Aid Posts and Rest Centres. helping evacuees and also as messengers at ARP posts. From December 1940 Girl Guides were able to wear the Civil Defence armband when engaged on voluntary support of the service or WVS.
I am indebted to Karen Wiles for the following images - learn more at Doing Their Bit.
News about interesting insignia, ARP related info and period photos that turn up.