First, blend the basil, olive oil and garlic cloves to form a smooth paste.
Place the lamb in a bowl and pour most of the basil oil over and stir the lamb well to cover. Leave for at least 3 hours, preferably overnight to marinate.
When ready to cook, preheat the grill and once hot grill the lamb for approximately 4 minutes with the lid down for pink meat. If you prefer your meat a little more well done simply leave to cook for another few minutes.
In the meantime simply toss the vegetables in the olive oil and lemon juice and season with salt and pepper.
Once the lamb is cooked, remove to a warm place to rest and open out the grill.
Cook the veg for a few minutes each side until coloured and softened.
Serve the lamb with the roasted veg and some olives, drizzle over a little of the remaining basil oil and enjoy.