Prepare the damsons – Wash the damsons thoroughly and remove any stems or damaged fruit.

Cook the fruit first – Place the damsons and water in a large saucepan and cook over medium heat until the fruit softens.

Remove the stones – As the fruit softens, remove the damson stones using a spoon.

Mash lightly – Use a spoon or potato masher to break down the fruit and release its juices.

Add sugar and lemon juice – Stir in the sugar and lemon juice until the sugar dissolves completely.

Bring to a rolling boil – Increase the heat and boil the mixture rapidly for 10–15 minutes.

Test the jam set – Drop a spoonful onto a chilled plate. If it wrinkles when pushed, the jam is ready.

Remove foam – Skim off any foam from the surface for a smoother jam.

Fill sterilized jars – Carefully ladle the hot jam into sterilized jars.

Seal and cool – Close the jars tightly and allow them to cool completely.