The National Portrait Gallery has always been a legendary London cultural landmark, and its newly refurbished Portrait restaurant on the rooftop is a fabulous spot for a pricey-ish lunch or dinner -- but it's also a great stop for tea or coffee and a sweet. BUT... Don't go between 3pm and 3:30pm, as they're transitioning between lunch and afternoon tea and you're out of luck.

A splurge for full on afternoon tea can be fun and filling, but not cheap (£24.50). Instead, just go for coffee and share a piece of cake and gaze at the view over Trafalgar Square on to Big Ben, Parliament and the London Eye.