Now that is
strange: whilst using Google
to look up the origin
this admittedly somewhat bizarre
British saying, the first record
... which looks like a quite familiar domain name.
However I digress. This is a fairly common phrase in the UK meaning
fairly intoxicated, or more precisely, very very drunk indeed. In fact
british slang seems to have a huge number of terms for this state of being,
including (but not limited to) bladdered, drunk as a skunk,
sober as a judge (this is what we call irony!), pissed as a newt,
Brahms and Liszt (rhyming slang), wankered
and no doubt many more which I can't currently remember.
Oh, and Google was of no help at all in finding the origins of the phrase.