Pedigree Chump

I wish websites that post works of art would credit the artist and give the date of his work. Here's a case in point I chanced upon while browsing the web for something else: Pedigree Chump. At first glance it looks like the work of that Yankee artist who used to paint Campbell soup cans, but a closer inspection reveals a talent for original humour that Whatshisname lacked. All I know of this graphic is that it hails from the Emerald Isle and shows a monocled English upper class twit with his monocled upper class twit dog. Nothing but grouse (flavour) is good enough for these two. Anyone know who designed it?