Place whole, unpeeled potatoes into a large saucepan and add water to cover. Bring to the boil then reduce heat and cook for 10 – 15 minutes or until potatoes are just tender. Drain and set aside to cool slightly. Chop potato into 1.5 cm cubes.
In a large bowl combine soup, mayonnaise, vinegar and black pepper. Add chopped potatoes, celery, green capsicum, spring onions and eggs, toss to coat. Cover and refrigerate for 1 hour or until chilled and ready to serve.