Tip the golden syrup into a saucepan, add the butter and heat gently until melted. Stir in the lemon juice, breadcrumbs, ginger and apples then leave to cool.
To make the pastry, put the flour, butter and lemon rind into a bowl and rub in the butter until the mixture resembles fine breadcrumbs. Add the measured water and mix to a smooth dough, adding a little extra water if necessary. Knead lightly, roll out and use to line a 24 cm (9½ inch) loose-bottomed tart tin. Trim off the excess and reserve.
Pour the syrup mixture into the tart case. Roll out the pastry trimmings thinly, cut narrow strips and arrange in a lattice, sticking the edges with a little milk. Then glaze all of the strips with milk. Place the tart on a hot baking sheet then bake in a preheated oven, 190°C (375°F), Gas Mark 5, for 40–50 minutes until golden and the filling has set. Cover the top loosely with foil after 30 minutes, if necessary, to prevent the tart burning. Set aside until required.
When ready to serve, warm the tart in a preheated oven, 160°C (325°F), Gas Mark 3, for 15 minutes or serve cold with clotted cream or vanilla ice cream.