The purists find it hard to agree what should go into a classic nicoise. Kim Terakes has sidestepped the issue by re-inventing the nicoise for the barbecue, using fresh grilled tuna and adding some capers to sharpen up the dressing.
Steam or boil the potatoes until just cooked, then cut in half and reserve. Hardboil the eggs and allow to cool, then peel and cut into quarters. Steam or boil the green beans and refresh in cold (preferably iced) water to maintain their colour and stop them cooking further.
Brush both sides of the tuna fillets with a little olive oil and season with sea salt and black pepper. Place on a preheated chargrill, turning just once until cooked to medium rare. Remove from the grill and set aside to rest, loosely covered with foil, for 5 minutes while you make the dressing.
Mix all the dressing ingredients together in a small bowl.
Divide the potatoes, eggs, beans, tomatoes, lettuce, olives, basil and anchovies evenly between four plates. Place a tuna fillet on top and spoon over the dressing before serving.