Wikipedia also goes along with the theory that ploughman's lunch was made up to sell cheese in pubs, though clearly people ate them before, but didn't call them that, which I am inclined to believe because of the L word. Hmm.
I grew up in a 'breakfast, dinner, tea' family. I am irked that I can't find a convincing map - I believe it to be a regional thing as well as a class based thing.
I am, however, amused at the Wikipedia juxtaposition:
'Afternoon tea is a mid-afternoon meal, typically taken at 4 pm, consisting of light fare such as small sandwiches, individual cakes and scones with tea.
High tea is a British meal usually eaten in the early evening.
Last meal is a meal served to a prisoner before his execution.'
ETA - in a newspaper so it must be true.
"It's not a big invention," said Carminantonio Iannaccone in a lilting Italian accent. "It's not like the telephone. It's just a dessert."
You need to read to the end for the bit about the inventor of the telephone.
(If you make something up, people will forget this and make up other explanations suggesting the thing is old English or 17th century Italian or whatever - see the naming of the octothorpe - origin disputed - http://en.wiktionary.org/wiki/octothorpe)