Add the raspberries, blackberries and the sugar syrup into the shaker glass, and then muddle all of the ingredients together. Add Brockmans Gin, fill the glass with ice and shake.
To serve, single strain the mixture into the tumbler. Top the rest of the glass with more crushed ice. Add a couple of blackberries and a raspberry, or skewer them for a garnish with a sprig of mint.
Fruit salad anyone?