Bring a medium pot of water to the boil. Add the potatoes and simmer for 10 minutes or until tender, adding the beans for the final 4 minutes of cooking. Drain and leave to steam dry until needed.
Meanwhile, bring a small pot of water to the boil and simmer the eggs for 8 minutes. Drain and run under cold water. Peel, quarter and set aside. In a small bowl, mix together the oil, lemon zest and juice with some seasoning.
Put the boiled potatoes and green beans, pitted olives, roasted pepper strips, tuna chunks and basil leaves into a large serving dish. Gently toss through the dressing (using your hands is best). Top with the egg quarters and serve.
Each serving 1 239kJ, 14g fat (3g saturated), 23g carbohydrate (7g total sugars).