What's the difference between a Bar and a Pub ? Well not much except pubs often have more than one bar and offer a variety of drinks.
Many of the Bars in London are often themed , so there are Wine Bars, Champagne Bars and many other themes.
Another trend is to have Bars in weird and wonderful places , be it on the top of a skyscraper or in a underground basement.
With the endless variety you will always find a bar to suit, but be aware some Bars are very expensive. Some of the best bars in London are The Artesian, The Nightjar,The Connaught, Happiness Forgets, Callooh Callay, American Bar at the Savoy Hotel, 69 Colebrooke Row, Zetter Townhouse, The Lonsdale, Baltic.