They lie about 36 km SW of Anzio: Ponza with its two islets of Palmarola and Zannone; and Ventotene further east. The chief attraction is Ponza. Its port takes car ferries but otherwise landing-places are few and there are only 12 km of rough roads. Tunnels in the volcanic tufa rocks communicate with outlying communities and provide access to postage-stamp-sized coves, grottoes and rough bastions of cliffs. A great deal of wild mountain scenery is crammed into Ponza’s few square kilometres. The town resembles a Greek island town: square, flat-roofed white houses, precipitous alleyways between high white walls. Ponza was a Roman playground, later a place of political exile. The Abyssinian princes lived here after 1936 and in 1943, after Mussolini’s overthrow, the carabinieri brought him here for some days before taking him to the Gran Sasso.

The spectacular beach is Chiaia di Luna, which you reach through a 0.5-km subway – a cool walk with a current of air even on the hottest day. ‘From what kingdom are you?’ Maria Aprea, aged 86, asked us, brandishing her Bible. The island is a small hotbed of Jehovah’s Witnesses, mostly returned emigrants from the U.S.

Sea services to Ponza and Ventotene from Anzio, San Felice Circeo, Terracina and Formia (summer only) take an hour (hydrofoil) or three (car ferry). From Fiumicino there is a fast catamaran to Ponza. From Anzio you could do Ponza in the day, spending about six hours there: long enough for a boat trip round the grottoes of Palmarola (you need a calm day for this). Ventotene has basic accommodation. Palmarola and Zannone are mostly uninhabited.