I'll get my coat

I've realised that while I, very occasionally, use the phrase "I'll get my coat", that I'm not entirely certain what it means or when it's used—possibly because I don't know the original reference but simply picked it up from cultural clues (mostly on the London.pm mailing list).

It seems to be a British thing, and to mean something along the lines of "I just said something that's embarrassing (or that may be potentially embarrassing and/or wrong), so I'll get my coat and leave"; is that about right? How would you explain when this phrase is used? Can anyone tell me its origin? I'm guessing a radio show or something.

Donating organs is love

Inspired by this entry of eilanhp's:

Donating organs is love

If you want to copy this somewhere, you can use this code:

<div style="text-align: center"> <div style="margin-bottom: 1em"><a href="http://www.livejournal.com/users/pne/376155.html"><img src="http://wunschzetel.de/pics/organs.jpg" width="360" height="60" alt="" border="0" title="Donating organs is love"></a></div> <div style="font-weight: bold"><a href="http://www.livejournal.com/users/pne/376155.html">Donating organs is love</a></div> </div>