This recipe comes from @suek who says "This is a refreshing sugar free drink. And best of all you can knock back as much as you want!" The trick is to make the pot of tea much stronger than you usually would (double the tea leaves or tea bags that you are using).
Pot of strong herbal tea
Sprig of fresh mint
Brew the tea triple-strength herbal tea - I used a berry flavour
Add a cinnamon stick if you've got one
Leave in the pot go cold, then strain.
Mix half and half with soda water
Serve with a sprig of mint and a cinnamon stick