Preheat oven to 180 degrees C. Grease baking trays.
In a medium bowl cream together the margarine, brown sugar and white sugar. Stir in the egg, water and vanilla. Combine the flour, salt, bicarb soda and cinnamon then stir into the creamed mixture. Finally, stir in the rolled oats. Drop by rounded spoonfuls onto the prepared baking trays.
Bake for 12 to 15 minutes in the preheated oven. Cool on baking trays for a couple of minutes before removing to cool on wire racks.