Café Royal Cocktail Book by W. J. Tarling (1937, p.122)

0.13 partlemon juice acid
0.25 partgin — Booth's dry ginbase
0.25 partsloe gin — Booth's sloe ginbase
0.13 partcuracao — Bols white curaçaomodifier
0.25 partdry vermouth — Noilly Prat vermouthmodifier
  1. Shake and strain into a cocktail glass.

Invented by W. J. Tarling and dedicated to E. Johansen of the Café Royal.