Bog-standard

I was reading a long list of British words when one in particular caught my attention: bog-standard. Whoooosh - a split-second rewind to October 2003 when I was first reading OotP - this is what I came across:

"Well, we thought it was a bog-standard chicken until it started breathing fire."

A vague understanding was instantly formed, namely that the chicken in question was not too out-of-the-ordinary, but perhaps by wizarding standards at best. And one could just hear the scratchings coming from the cardboard box.

Fast forward to the present. This is the definition of bog-standard: (UK, somewhat derogatory) ordinary, basic. So there is definitely no wizarding connection. A Google search yields about 349,000 results, and obvious muggle ones at that (as opposed to stuff like "spellotape" and "blast ended skrewts", which yield results in their thousands). And when you try to find out its origins, you find out that everyone else is just as mystified as you are! It seems that this quirky, colourful little phrase just came out of nowhere and latched itself effortlessly onto the public psyche.

Bog-standard, I ask you? Gotta love the British.