On Tuesday, January 3rd, 2012, at 18:57:44h +0000, J P Gilliver wrote:

I was quite impressed the first time I saw what I think of as the
"Dutch" design: a bit like the Schuko, but the earth is actually a
socket in the plug, and a pin in the socket! Thus if you try to plug in
a plug that doesn't have the socket, it won't go in!

As far as I am aware that design was not created in the Netherlands but
is in fact the design of the French and is "NF" (la norme francaise)

http://www.marque-nf.COM/

It is the equivalent of BSI kitemark branding.

This design of round three pin plug was adopted by France of course,
and also Belgium and the Netherlands.

Thus round pin plugs on equipment sold in Europe have both the
earth pin socket on the plug and the side earth pin springs to
enable them to be used in France, Benelux, and Germany and other
states.

And to be different being an "insular" nation, the Swiss have
something different completely.