English High Tea usually involved a mug of tea, bread, vegetables, cheese and occasionally meat. Variations on high tea could include the addition of pies, potatoes and crackers.
So while Afternoon Tea was largely a social event for their upper class counterparts, high tea was a necessary meal in the eighteenth and nineteenth centuries. This traditional high tea still exists for some parts of the North and Scotland.
Why is it called ‘high tea'?
A possible explanation why this type of meal was called high tea is the fact that it was eaten at a table. In comparison, Afternoon Tea was taken whilst seating in low, comfortable chairs or sofas. Of course, soon after, the upper classes developed their own variation and also called it ‘high tea'. It was a meal that could be eaten when their servants were away or not available, as it was so easy to prepare. The upper class ‘high tea' involved the amalgamation of Afternoon Tea and high tea, with the addition of pigeon, veal, salmon and fruit.
http://www.afternoontea.co.uk/index.php?option=com_content&task=view&id=838&Itemid=36#.UWbboPISR8E