Reserve one rosemary sprig for garnish. Add the gin, juices and sugar syrup to a cocktail shaker, add plenty of ice and shake vigorously until chilled. Strain into a chilled rocks glass, add one large ice cube and top off with ginger beer. Garnish with the reserved rosemary sprig.
Add all the ingredients to your Tesco, Ocado etc. baskets.
Note: Use beetroot juice from a carton if you don’t have access to a juicer. A quarter of a grapefruit yields approximately 12.5ml juice.