Pret A Manger

You're in Mayfair, surrounded by swish offices and investment banks, so when you duck into this Pret on Berkeley Square, you're joining the local workforce grabbing their morning fuel. It's the kind of place where everyone knows what they want—a flat white and a crayfish sandwich, usually—and the queue moves fast because it has to. The space itself is nothing to write home about: fluorescent-lit, a few stools by the window, the hum of a proper espresso machine. But that's precisely why it works. You get genuinely good coffee here, not the burnt stuff some chains peddle, and their sandwiches are fresh enough that you don't feel like you've compromised on taste just because you're in a hurry.