Caffè Concerto Northumberland Avenue

You're steps from Trafalgar Square's chaos, but inside this sprawling Italian-style café, the theatre crowd mingles with tourists over towering slices of tiramisu and proper espresso. The glass display cases packed with elaborate cakes are impossible to ignore – think black forest gateau that looks like it belongs in a Milanese pasticceria rather than central London. The menu runs from breakfast pastries through to evening pasta, but really you're here for the desserts and decent coffee. It's reliably busy thanks to the prime Northumberland Avenue location, catching everyone from West End show-goers to office workers ducking out from nearby Whitehall. Service moves at a clip, which you'll appreciate when you're racing to curtain up at one of the nearby theatres.