Boil potatoes until they are tender. They are cooked when a knife will pass through them easily. Drain potatoes and chill in a bath of iced water. When potatoes are cool, cut them into bite size pieces and place in large bowl or pan.
While potatoes are cooling, cook bacon in a large pan until it is crispy. Drain excess fat and let bacon cool.
Add sour cream, mayonnaise Dijon mustard, diced scallions and chopped bacon to potatoes and mix together well. Try not to crush/mash the potatoes wile mixing. Add plenty of pepper and salt to taste.