Preheat the oven to 220°C/425°F/gas mark 7.
Blanch the potatoes and beans in boiling water for 5 minutes, then drain and set aside.
In a large, deep baking tray, mix together the oil and lemon juice, then put the fish in the tray, side by side.
Put the potatoes on the fish, then scatter the French beans, olives and anchovies all over the top.
Season with black pepper and bake in the oven for 40 minutes.
Garnish with fresh parsley and serve with bread - wonderful to mop up all the sauce.