In a large pan, add the chicken pieces with the carrots, celery, leek tops, bay leaves, peppercorns, and thyme. Cover with water and bring to a gentle boil. Cook the chicken for 1 hour until cooked through and tender.
Remove the chicken and set aside to keep warm. Strain the stock, reserving the stock.
Wipe the pan clean and add the stock with the leek tops and pearl barley. Bring to a boil and cook for 35-45 minutes until the pearl barley is tender.
While the barley cooks, shred the chicken. Add the prunes and shredded chicken back to the stock when the barley is tender. Season to taste with salt and lots of pepper.
Garnish with chopped parsley.