The secret of a great hotel, regardless of history or aesthetic, is the ability to pluck the casual visitor from the street and tuck her into a cocoon so transportive that the outside world sublimates. The Beaumont in Mayfair is every bit the afternoon off the grid you deserve. For lunch, melt into a delicious benedict or a salad that seems to replenish itself every few bites. Hours will pass – don’t bother resisting. In the evening you’ll be back for a nightcap and tea sandwiches, the perfect midnight snack.