Butter a 1.2 litre pudding basin and pour 2 tablespoons of the golden syrup into the bottom.
Beat the margarine and sugar together until pale and fluffy, then beat in the eggs one at a time, adding a spoon of the flour with each to stop the mixture splitting.
Fold in the remaining flour and baking powder along with the milk, until you have a soft dropping consistency. Spoon the mixture carefully over the syrup in the basin.
Level the top, put a pleated circle of baking paper and a sheet of foil over the basin and tie them down with string, then lower it into a pan of simmering water so the water comes halfway up the sides.
Steam for 1 hour 45 minutes, topping up the pan with boiling water now and then. A skewer pushed through the foil should come out clean.
Rest for 5 minutes, run a knife around the edge and turn the pudding out onto a warm plate so the syrup runs down the sides. Pour over a little warmed extra golden syrup and serve.