Place the apples, pears, peaches, apple juice, water and mixed spice in a heavy-based saucepan. Set the pan over a high heat and bring the fruit mixture to the boil, stirring occasionally.
Reduce the heat to low and simmer, uncovered, for 30 minutes or until the mixture is reduced to a pulp and no liquid is visible on the surface. Stir frequently to prevent the mixture from sticking to the bottom of the pan.
Remove the pan from the heat and allow the mixture to cool slightly. Taste the mixture and stir in the lemon juice if it is too sweet.
Transfer the fruit mixture to a food processor or blender and process to a thick purée.
Leave to cool completely before serving. The spread can be kept, covered, in the refrigerator for up to 2 weeks.