1. Bring the water, sugar and mint leaves to a boil and simmer until the sugar has completely dissolved. Leave the mixture to cool.
2. Stir in the lemon juice. Pour the mixture through a sieve.
3. Fill eight ice pop molds 3/4 full with the mixture.
4. Add one or two mint leaves and blueberries to each mold.
5. Place the ice pops in the freezer for at least four hours.