FURTHER my contention that the real gastronomic creativity in London is happening in bars rather than kitchens here is a snapshot of the Zetter bar – across the courtyard form the hotel (it is a bit confusing as to which Zetter is which).
Here we have a set up that Rimbaud and Verlaine might have approved from the streets of 19th century Paris, the absinthe strained through a sugar cube, although in fact here, interestingly, the absinthe is in fact made in Cornwall, tinged with seaweed, named after a mermaid. Fine stuff, very licoricey. the sugar has quite a dramatic effect.
Not on the menu but you can ask for it is a supreme nightcap of whisky with sweet vermouth and sandalwood. 
The long railway carriage of a room has been plumped with antiques, a bit Phileas Fogg, or your great great uncle’s study
There are some other tricks at work such as a blue martini and so called stone washed gin – they have a separate laboratory where they concoct things like hopped tarragon cordial, so it is all very exciting and original, an adventure.
Plus some food in small doses to match like this oyster in buttermilk
and this pomme souffle filled with cod’s roe and topped with vegetarian caviar.
. Worth checking out.
https//www.thezettertownhouse.com/clerkenwell/bar
101greatrestaurants.com 