Cook potatoes in salted water until fork tender.
While the potatoes are cooking, in a large skillet cook bacon until brown and crisp. Remove and place on a paper towel to drain. Drain potatoes and let stand until cool.
Peel and slice into a large bowl, add bacon and keep warm, covered with the fat from the bacon and add the onions and celery. Cook until soft about 3 to 4 minutes. Add the sugar, vinegar and stock, and then simmer for about 2 minutes.
Add liquid mixture to the potato and bacon. Add the parsley and toss together.
Season with salt and pepper.