Pre-heat the oven to 200C/Fan 180C/400F/Gas Mark 6. Tear the bread into bite sized pieces and place in a roasting tin. Drizzle over half the oil and toss to coat the bread. Bake for 15-20mins or until the bread is golden and crunchy.
Cut the tomatoes and peppers into bite sized chunks and place in a large bowl. Add the onion, olives, remaining oil, vinegar and basil.
Season well with salt and freshly ground black pepper then toss together with the bread. Leave to stand for 5 mins to allow the flavours to infuse.
Finally tear the lettuce into bite sized pieces, add to the bowl and toss until well mixed.
Serve straight away