The 'SFP' armband is quite a rare one as they were changed to 'Fire Service' shortly after their introduction and often oversewn.
Over to aBay for her take on this....
This SFP Armband is a unique piece of militaria that belongs to the Armband type of clothing. It was issued during the World War II era, specifically between 1914-1945, and was manufactured in the United Kingdom. The armband is a collectable item that showcases the theme of the Home Front/Civil Defence service during the war. The armband is a rare find for collectors and enthusiasts of militaria. It represents the courage and resilience of the British people during a time of great adversity.