Put a pie funnel in the centre of a 1 1/2 pint (900 ml) pie dish.
Cut the rhubarb into 1 inch (2.5 cm) lengths and mix all the fruits together; put half in the bottom of the pie dish and sprinkle with the sugar.
Cover with the remaining fruit and add 2 tablespoons water.
Make the pastry up as usual and then roll out on a floured table and cover the top of the pie dish; use any trimmings to decorate if liked.
Chill in the refrigerator for 30 minutes.
Heat the oven to 400°F, 200°C, gas no. 6.
Brush the pie with a little milk and sprinkle the top with granulated sugar; make a small slit in the centre for the steam to escape.
Bake in the oven for 40 to 45 minutes until the fruit is tender and the pastry crisp and a pale golden brown.