Place whole potatoes in saucepan of cold water. Bring to the boil then turn down the heat and simmer potatoes for 15 to 20 minutes, depending on the size.
Drain Perlas well and then place in a large bowl with garlic, lemon juice and olive oil. Season with pepper and toss well, then set aside to cool.
Meanwhile, prepare red pepper, onion and tomatoes and add to cold Perlas. Toss well. Scatter with cubed feta, Kalamata olives and torn basil and serve.