I would love to know the different meanings of "tea" in current usage in the U.K. I know that it can be the usual lovely cream tea one takes at four, while at the same time it means a light dinner around 5 or 5:30. I wonder about different class meaning of the expression.
In West Yorkshire, where I grew up, "tea" is the main evening meal, so we have breakfast/dinner/tea rather than breakfast/lunch/dinner. The same is true, I think, of most of the North of England.
I'm gradually learning to describe the middle meal as "lunch" when talking to the rest of the world, but it's a hard habit to break.