I have a coaster with the picture of a beard man, which says:

BRITONS WANTS YOU

I got it at a sourvenir shop the other day. But I don't really understand why this is not :

BRITONS WANT YOU

as I think that "Britons" is plural and don't need trailing "s" for "WANT".

Similary, on the bottom of the coaster there is another thing :

GOD SAVE THE KING

, not "GOD SAVES THE KING". This also sounds funny as I think "GOD" is a singular noun.

Could anybody explain this for me ?