Preheat the oven to 200C/400F/Gas 6.
Grease and flour four dariole moulds.
Roll out the pastry and carefully line each of the moulds, retaining enough pastry for a lid for each pie.
In a mixing bowl, stir together the blueberries, blackberries, lemon juice and zest, cinnamon and sugar. Fill the moulds with this mixture and place on a baking sheet.
Top and seal with the remaining pastry. Make a slit in the top of each pie to release steam.
Brush with egg and cook for about 20 to 30 minutes, until the top is browned.
Once cooked, allow to rest, before removing from the mould.
Boil together the jam and water to make a glaze. Using a pastry brush, smear the glaze over each pie.
Serve with clotted cream.