Ingredients

150g Co-op British blueberries
Zest and juice of 2 lemons
75g Fairtrade caster sugar
Sparkling water, to serve

Method

For the blueberry syrup:

Simmer the blueberries in 150ml water, juice and zest of 1 lemon, and caster sugar in a pan for about 5 mins, until the berries have broken down
Push through a sieve, then leave the liquid to cool
Store for up to a week in a 250ml sterilised bottle (wash it in hot, soapy water first, then put in the oven on a low heat for 10-15 mins)

For the mocktail:

Pare the zest of the other lemon and set aside. Squeeze all the lemon juice into a jug, then pour in 100ml blueberry syrup, or more to taste, and stir to combine
Add lots of ice and twists of lemon zest, then top up with sparkling water