I'd hoped it wouldn't come to this but I've known since he was four months old that he had separation anxiety and it's escalated to the point that he's inappropriately pooping/peeing when I'm away.
So, the vet has suggested Clomicalm which I can see has been suggested by other vets for members here but there doesn't seem to be any posts about the long term success.
He'll be seeing a behaviorist, too.
Aw, Teddy.