Cover potatoes with water in large pot. Bring to the boil over high heat.
Reduce heat to low and simmer until potatoes are tender, about 10 minutes; drain.
Return potatoes to the pot, turn off the heat and mash. Stir in the milk, Knorr Chicken Stock Pot, and Stork Margarine until melted.
Season mash with Robertsons Ground Black Pepper.