Hey, it’s a bit of a slow day… :-)
Sure, it’s an ‘adjustable spanner’ over here, but ‘monkey wrench’ is a well known term too.
Hey, I had a quick search and I discovered a couple of things: adjustable spanners and monkey wrenches are not quite the same thing, as its usage varies, and the ‘Moncky’ story is regarded as apocryphal by historians…
http://en.wikipedia.org/wiki/Monkey_wrench
http://en.wikipedia.org/wiki/Adjustable_spanner