Instructions

1. Carefully wash the blueberries. Wash then collect the zest and juice of the limes.
2. Put the blueberries, lime zest & juice and the sugar into a large heavy-based pot.
3. Gradually bring to the boil, stirring gently but constantly with a wooden spoon, then reduce to a simmer. Cook for half an hour or so until it reaches setting point (see tip).
4. Take off the heat and allow to to cool a little before sealing into sterilized jars.