We have Anna the 7th Duchess of Bedford to thank for this marvelous pass time. She complained about “having that sinking feeling” during the late afternoon as it was common during the early 19th century to take only breakfast and dinner. Her very sensible solution to this was to take a light meal between the two. Eventually, after inviting friends to join her and taking the trend to London, it became the fashion to gather with friends to enjoy tea and sandwiches.
These days Afternoon Tea is saved mainly for special occasions, and having tried to attempt a full tea before myself I can understand why, without a kitchen of cooks, we now leave it to the hotels and cafes to indulge us.
Marie At Tea 
According to a VisitEngland press release I received today, afternoon tea is still served in traditional form in the Duchess’ tea room at Woburn Abbey for £12.50 per person. http://www.woburn.co.uk/abbey/ Thought you might like to know!!
I’d be very interested in visiting the abbey to try it out actually. And the price seems very reasonable, plus it will be good to try a few more Teas outside of London. Thanks for the tip.