What places like Curators Coffee Gallery (check the Curators Coffee Gallery article) are to coffee, places like Yumchaa are to tea. These guys have several locations in London, all of them worth checking out for the excellent range of loose-leaf teas. You can sniff them all as you approach the bar to make sure you’re happy with your choice. I’d also recommend the chai latte.
This Yumchaa location is my personal favourite, though, because it’s so perfect for working. The space is expansive, with seating for every occasion: individual armchairs, tables large and small, and squishy sofas for group languishing, but it’s also large – very large, for a London café – and so you can tap away at your incipient novel all afternoon without anyone minding, or perhaps even noticing. In fact, if you sit in a the desk area over to the right, you’ll probably feel naked without a laptop in front of you. Perfect for productive afternoons.