This is a gorgeous black leather handbag dating to the 1950s or possibly early 1960s by Nil Simile, a well-known British shoe manufacturer of the period. 
In fantastic condition, with a tan suede interior, subtle red top stitching and label in place, it only has a few marks on the inside indicating it may have been used only once or twice in its life!
A stunning addition to any retro collection or vintage costume.