This stunningly located restaurant above the National Portrait Gallery offers dramatic views over Trafalgar Sq and down to the Houses of Parliament and London Eye. Prices are a bit steep, but dishes such as twice-baked Montgomery cheddar soufflé with kale, salsify and lime pickle justify the price. The ideal break from hours of portrait-gazing; it's best to book ahead.
Not all lifts go to the floor with the restaurant, and some signs within the museum don't mention it at all, so ask for directions or head for the lifts in the centre of the building.