Pre-heat oven to 180°C / 160°C fan assisted /gas mark 4 / 350°F and line and grease an 8 x 4 inch deep square cake tin.
Put the sugar, treacle, syrup and milk into a medium saucepan and heat, gently stirring until the sugar has dissolved but turn off the heat when the mixture reaches just below boiling point. Allow to cool slightly.
Sift together the flours, bicarbonate of soda, baking powder and spices in a large mixing bowl.
Add the butter and rub into the flour mixture until it resembles fine breadcrumbs.
Mince the stem ginger and fresh ginger very finely with a sharp knife and whisk into flour mixture until evenly dispersed.
Pour the treacle mix over the dry ingredients and stir to combine.
Finally beat in the eggs.
Pour into the cake tin and bake for 40-45 minutes.
Remove from the oven, transfer to a wire rack and leave to cool completely before dusting with icing sugar.