Quote from : The Pleasures of Afternoon Tea Book

The hour [...] can be anywhere between three and six o'clock in the afternoon. The general rule is that the earlier tea is served, the lighter the refreshments. At three, tea is usually a snack -- dainty finger sandwiches, petits fours, fresh strawberrries; at six, it can be a meal -- or "high" tea -- with sausage rolls, salads, and trifle.