Make a pastry by the margarine into the flour, and adding enough cold water to bind it together.

Roll the pastry out and make a lid for the pie using your pie dish as a template.

Line the dish with the remaining pastry.

Put the raspberries and bananas into the pie dish, adding sugar to taste.

Put the pastry lid on, brush it with water and sprinkle brown sugar over.

Bake in a moderately hot oven for around 30 minutes, until golden brown.