Wash the blackberries well to ensure they are clean. Be sure to use ripe berries and remove any that are underripe or going bad.

Place the water, sugar and blackberries in a small pan and place over a medium-low heat, uncovered.

Stir the mixture gently as you bring it to a simmer to ensure all the sugar dissolves. As it warms, the blackberries will start to go lighter in color - this is fine. Mash the berries to break them up and release the juices. Once it comes to a simmer, reduce the heat and simmer for around 3 - 5 minutes more - the mixture will start to look a little darker in color - then remove from heat. Set aside and leave the berries in the syrup to infuse it further as it cools.

Pour the syrup through a strainer/sieve to hold back all of the fruit solids and seeds. Use a fine strainer as some of the seeds can be small and you don't want them sneaking through. Store the syrup in a sealed bottle/jar in the fridge until needed.