While the SAS traces its origins to 1941 and the Second World War, it was reformed in 1947, and named the 21st Battalion, SAS Regiment, (Artists Rifles). The 22 SAS later gained fame and recognition worldwide after successfully assaulting the Iranian Embassy in London and rescuing hostages during the 1980 Iranian Embassy Siege, lifting the regiment from obscurity outside the military establishment.
The Special Air Service presently comprises 22 Special Air Service Regiment, 21 Special Air Service Regiment and 23 Special Air Service Regiment. It is tasked with special operations in wartime, and primarily counter-terrorism in peacetime.
As always, the artworks featuring the insignia are available via my “Military Insignia” galleries from FineArt America and RedBubble. You can just follow the links in the article to get to the corresponding galleries.
To active duty or reserve military personnel, veterans and their family members: I grant an explicit permission to download the above images to be used for non-profit/non-commercial and charitable causes, benefiting troops and their families, as well as for non-commercial internal duty-specific purposes, such as unit website design, training materials and presentations. Please, contact for any other intended use.
The above information provided in part by Wikipedia, The Institute of Heraldry, Global Security, and the official websites of the corresponding units and formations.