MrsDangermouse
Guru
I suspect you mean Afternoon Tea?Other question what are the occasions for High Tea?
High Tea is a proper evening meal with its origins firmly with the working classes - it was usually eaten around 6p m when people got home from hard day's work and could be anything from bread and butter to a fully cooked meal. The reason its called high tea is because its eaten at the high (ie. dining) table. So there is no special occasion calling for it - it was just a normal every-day meal.
On the other hand, Afternoon Tea was invented by the aristocracy to bridge the gap between lunch and dinner (their dinner was usually served quite late). It usually consisted of delicate sandwiches, scones and cakes and was served at low tables mid-afternoon (hence the name Low Tea or Afternoon Tea). Nowadays it tends only to be something you'd do for a special treat or to celebrate in genteel surroundings.