Knickerbocker

For the syrup, put the sugar and 120ml water in a saucepan over a medium heat and heat, stirring, until most of the sugar has dissolved. Add the berries and cook for 10 minutes, stirring occasionally, until jammy. Remove from the heat and cool for 15 minutes, then strain through a sieve, pressing down on the fruit with a spoon to extract the juices. Leave to cool; it will thicken slightly.

For the cocktail, put all the ingredients except the berries and lime wedges in a cocktail shaker with plenty of ice, and shake until cold. Taste, adding a little more syrup or lime, depending on how sweet or tart you like it. Strain into a tumbler filled with crushed ice. Garnish with berries and a lime wedge or two, if liked.