Bring the chick peas to the boil and simmer until tender (about 30-45 minutes). Don’t salt the water, though, or the chick peas will not soften.
The topped and tailed haricots will need 3-4 minutes in boiling salted water, then drain them with cold water and cut each bean in half. Combine the mayonnaise, anchovy fillets, spring onions, capers and chopped parsley, then season with salt and pepper. Fold the drained chick peas and green beans into the mayonnaise mixture together with the black olives.
Taste and add a little lemon juice and more seasoning if necessary. Serve on a bed of crisp lettuce leaves.