In a large saucepan, over medium-low heat, fry the bacon until browned but not crisp, about 5 minutes. Spoon off and discard all but 2 tablespoons of the drippings. Add the leek, thyme leaves, salt, and pepper. Cook for 5 minutes. Add the milk and potatoes. Simmer gently until the potatoes are almost tender, about 15 minutes. Add the corn and cook for 5 minutes. Add the nutmeg and ladle into bowls.