Boil pasta according to the packet directions then drain and cool in a colander under cold running water. Shake dry then pour in large bowl.
Stir in bocconcini, cherry tomatoes, radicchio, spring onions, corn, pine nuts and olives. In a small bowl stir together pesto, sherry, salt and pepper. Toss into the pasta salad then garnish with basil leaves. Serve right away or refrigerate and serve later.