Gently melt treacle and margarine in a pan - remove from heat and allow to cool a little.
Add all dry ingredients into the pan with the melted margarine and treacle. Stir until it all combines into a ball of biscuit dough.
Turn out onto work surface and cut the ball of dough into 8 portions by cutting into quarters then half each quarter again. (You can make it into small portions of 16 small balls if desired for smaller biscuits)
Roll into balls and place on grease proof paper on a baking tray. (Flatten slightly with fork for lines).
Bake in a preheated oven 200C/180C Fan/400F/Gas Mark 6 for 10-12 minutes (depending on size of biscuits)
When cool drizzle glace icing over biscuits or just leave them as they are if you prefer!