Typically middle/upper class English male from good breeding and background. Usually old money, and has attended Oxford and/or Cambridge and hails from one of the home counties. Typically an Eton boy, enjoys eating cheese and wine in their smoking jacket and listening to classic FM's Evening Concert.
The Jenkins is traditionally spotted at either Henley or Marlow regatta, and usually wears some sort of hideously coloured striped boating jacket.
Not to be confused with the Made In Chelsea-esque character, Jenkins are far more superior (in their eyes) and are more "quintessentially English".
"Look at this Jenkins twat at the Henley Regatta!"
"I say there Jenkins- you give me that look one more time I might get in my PJs and have a pillow fight with you."