To make the suet crust, sift the flour with the salt and stir in the suet. Add enough water to make a soft, slightly sticky dough. Knead briefly, dusting with flour to get a smooth, elastic dough. Roll out on a generously floured board to a thickness of about 5mm. Blanch the leeks in boiling water for 1 minute. Drain thoroughly.

To cook the pudding in a pressure cooker, line a shallow basin or colander with a large square of silver foil. Line this with the suet pastry, then place the chopped leeks (and bacon or meat, if using) inside and season generously. Lightly flip the pastry over to cover the filling loosely. Don't worry about sealing the pastry tightly - as it cooks it will rise and seal itself. Wrap the pudding loosely with silver foil. Fill the pressure cooker with water to a depth of 5-7.5cm, heat and when hot, stand the pudding inside, cover tightly and cook for 15-20 minutes.