My favorite is The Connaught. At 16 Carlos Place in Mayfair, I had tea there at the Espelette Restaurant, 40 years after having my first high tea there with my parents. It is a wonderful, elegant hotel with great bar and restaurant.
I also tried The Modern Pantry. I stopped in for a cup of tea and dessert on a Sunday afternoon at 47-48 St. Johns Square in Clerkenwell. Their regular afternoon tea during the week and on Saturday was featured as one of the best new places to have tea in London. It is a bright, contemporary restaurant with nice patio seating.
Recent articles highlight The Anthenaeum Hotel, Gilbert Scott Restaurant at the St. Pancras Renaissance Hotel, The Gentlemen’s Tea at the Reform Social, the Savoy, Townhouse Tea at Dean St. Townhouse, Mad Hatters Tea at the Sanderson, Coutour Chocolate Tea at The Halkin, The Lanesborough, Sketch at Ten Manchester St., and Hotel 51 Buckingham Gate.