Regular services on the Cairo to Basra route began on 12 January 1927 using DH.66 aircraft, replacing the previous RAF mail flight. Following 2 years of negotiations with the Persian authorities regarding overflight rights, a London to Karachi service started on 30 March 1929, taking 7 days and consisting of a flight from London to Basle, a train to Genoa and a Short S.8 Calcutta flying boats to Alexandria, a train to Cairo and finally a DH.66 flight to Karachi. The route was extended as far as Delhi on 29 December 1929. The route across Europe and the Mediterranean changed many times over the next few years but almost always involved a rail journey.