Located at 3 St. James Street since 1698, Berry Brothers. & Rudd is Britain's oldest wine merchant. The shop has the quality of a (very expensive) museum. Its underground cellars, previously part of Henry VIII's royal residence and later a hideout for the exiled Napoleon III (the famous Napoleon's nephew) have been converted into meeting rooms.
However, a secret tunnel, now blocked by wine bottles, leads to St. James Palace. It was used by philandering royals to pay clandestine visits to the ladies of the night who hung out at the shop in the 18th century. Or perhaps they just wanted a nightcap.