Mum’s leek and potato soup

Peel and chop four potatoes, one onion, one garlic clove and two celery stalks and place in a pan. Cover with water, bring to the boil and simmer for 8 minutes. Add the white part, sliced, of three leeks and cook until tender. Whizz with a blender. Add a knob of butter, a small carton of single cream and some chopped parsley. Serve with crusty bread.