The 38th Middlesex (Artists') Rifle Volunteers was formed, in response to a threat of invasion by Napoleon III, by Edward Sterling in London with headquarters initially at Burlington House, where the war memorial is. The artists, in at least some respects, behaved just like most soldiers: their bawdy marching songs, included 'Mary Had a Little Lamb' which one volunteer remembers as "remarkable for having 11 verses, only one of which was respectable, and that one was usually left out". Lots of information at the Picture source website.
The unit's badge, designed by L. C. Wyon, shows the heads of the Roman gods Mars and Minerva in profile, representing war and wisdom. According to the Artists Rifles Association it was also “the title of the first Regimental March, the words of which were written by an Artist, George Cayley *. A regimental rhyme records: ‘Mars, he was the God of war, and didn't stop at trifles. Minerva was a bloody whore. So hence The Artists' Rifles.’”
Also known as the "20th Middlesex","28th Battalion, the London Regiment" and various other similar names. We have to admit we don't understand the naming conventions of the armed forces.
The regiment was disbanded in 1945, reformed in 1947 and transferred to the Army Air Corps as the 21st Special Air Service (Artists Rifles) – the SAS.
* The only George Cayley we can find is a scientist and pioneer of aviation.