Evelyn Waugh's Noonday Reviver
1 hefty shot of gin
1 (1/2 pint) bottle of Guinness
Kingsley Amis - 'Put the gin and Guinness into a pint sliver tankard and fill to the brim with ginger beer. I cannot vouch for the authenticity of the attribution, which I heard in talk, but the mixture will certainly revive you, or something. I should think two doses is the limit.'
O to move in such exalted circles.