Soak the anchovy fillets in a little milk to remove excess salt.

Remove the root, coarse outer leaves and green top from the leek. Slice the white part into rings, then rinse well and drain. De-seed the pepper, wash, dry and dice.

Heat the oil in a shallow pan, add the leeks and the anchovies, drained and chopped.

Mix well, cook for a few minutes over a low heat, then add the chopped pepper. Peel the tomatoes if using fresh ones; drain if canned. Slice and add to the pan with the stock, wine or a mixture of both. Season with salt and pepper and leave to simmer for 20 minutes. Just before the end of the cooking time add the chopped olives and tuna.

Cook the pasta in a large pan of lightly salted boiling water until al dente. Drain and put in a heated serving bowl.

Add the sauce and mix well. Sprinkle with Percorino cheese and chopped basil and mix again before serving.