Put the blackberries in a very large bowl and crush with a ladle or potato masher. Pour the red wine over and stir well and cover with clingfilm. Leave in a cool place for 24-36 hours, visiting it occasionally for a stir.
Next, cover a pan with a square of muslin or a double thick J-Cloth. Strain the fruit and wine through the cloth, pick up the edges and gather them together, twist to squeeze out as much juice as possible.
Add the sugar and stir, bring to the boil then reduce the heat and simmer for 45-60 minutes until it thickens. Taste and check if it is sweet enough, if not add a little more sugar to get it right. Cover and cool completely, stir in the brandy and then pour into sterilised bottles. Store in a cool dark place.
