This is our signature aperitif at Gymkhana restaurant in London. The citrus makes it a very refreshing palate-cleanser that helps take the edge off the working day. One is never enough, three perhaps too many. Serves one.

60ml London dry gin
8 dashes Angostura bitters
120ml tonic water (we use Fevertree)
1 good-sized wedge each fresh lime, lemon and grapefruit

Pour the gin, bitters and tonic into a tall glass over lots of ice, squeeze in the juice from all the fruit and serve at once.

• James Stevenson, group head bar manager, JKS Restaurants.