Peel and wash the carrots and cut them into fine sticks. Drain the corn. Clean, wash and cut salads into wide strips. Clean and wash rocket and pluck off the thick stems. Leek onions clean, wash and cut into rings.
Mix all salad ingredients. Whip buttermilk and lemon juice. Season with salt, pepper and sugar. Put the salad in a bowl. Pour buttermilk dressing over the salad, fold in and serve immediately.