Place the gin, tonic water and white granulated sweetener in a measuring jug and stir until the sweetener has dissolved.
Place half a lime slice in each ice lolly mould. Add 4 blueberries and 2 mint leaves to each.
Pour the gin and tonic mixture into each lolly mould. Leave a small gap at the top as the mixture will expand when freezing. Place a lolly stick in each and place in the freezer for a minimum of 8 hours or overnight, until solid.
When ready to serve, dip the lolly mould in hot water to loosen the ice lollies. Remove the ice lollies and serve at once.