Did you perhaps misunderstand the waitress? She could reasonably expect you, or another customer, to have got hold of her or the manager while the dog was actually licking its owner's cup and plate.
They don't have eyes in the back of their heads, so a discreet hint might have been needed and acted upon.
She neither could, nor should have expected you or anyone else to have risked an embarrassing scene by saying anything.
I would myself have done so, but that has really nothing to do with the issue.
I just do not fathom that it is still legal to take dogs or other animals into places where food is served or made in the UK.
Fond as I am of animals I would never dream of eating off a plate a cat or dog has used!
Books we loved when we were young
Is it rude to not finish a book club choice that was selected by someone else?


