It's been happening all week - because it's http://www.britishsandwichweek.com/ .
Most people think they know the origin of the Sandwich ( the Sand Wich Project being the prequel to the Blair Wich Project etc etc ) - but this is incorrect. Sandwiches go back much further in time. I found a very old pastrami sandwich at Stonehenge. Very old.
Most sandwiches are also tone deaf apparently - but the one that came in ear on Monday was clearly kind of musical - in a sandwichy kind of way.
The sandwich song it was singing didn't make much sense to me - but this is what my pink-pidgin-english recorder app made of it: