Peel the potatoes and cook in salted boiling water until just tender.

Meanwhile finely chop the onion; drain and chop the anchovies. Put 2 tbsp of the oil in a shallow pan over a medium heat, add the onion and anchovy and cook until the onion is golden. Slice the tomatoes then add to the pan.

Add red pepper to the pan with the tomato mixture, stir briefly then add half the stoned and chopped olives. Moisten with vinegar, leave for a few seconds, then turn off the heat but keep the pan warm.

Drain the potatoes and cut into slices while still hot. Put in a large salad bowl and pour the prepared sauce over. Add the remaining oil, the oregano, a little salt and plenty of pepper. Mix well and serve while still warm. Garnish with a few whole olives.