Wash the potatoes, bring to the boil covered with water and cook for about 20 minutes. Drain potatoes, peel and let them cool down. Mix yoghurt and salad cream and season with salt and pepper.
Clean, wash and cut the spring onions into rings. Wash and halve the tomatoes. Clean rocket and pluck small. Drain tuna and cut into bite-sized pieces. Wash and chop parsley.
Cut the potatoes into slices and add them to the yoghurt. Add spring onions, tomatoes, rocket, tuna and parsley. Mix everything together and let it soak well. Season again with salt and pepper.
Arrange on plates.