Manoeuvring in two groups to increase the chance of intercepting the convoy had succeeded for the Italians but sacrificed the benefits of concentration against the escorts and a destroyer was lost for no result.

The British command at Aden criticised the escorts (excepting Kimberley) for a lack of aggression but leaving the convoy defenceless to chase ships at night and in misty weather would have been risky.

[1] From May to June 1939, French and British military officials met at Aden to devise a common strategy to retain control of the waters around Italian East Africa if Italy declared war.

[2] The British-controlled Port Sudan, lay on the west coast of the Red Sea, about halfway [600 nmi (1,100 km; 690 mi)] between Suez and the Bab-el-Mandeb Strait (باب المندب, Gate of Tears).

Massawa was the home port of the Red Sea Flotilla (Flottiglia del mar rosso) commanded by Rear-Admiral [Contrammiraglio] Mario Bonetti, from December 1940 to April 1941.

[3] The scout cruisers (esploratori, also Leone-class destroyers) Pantera and Leone (Commander Paolo Aloisi) had an unusually powerful armament of eight 4.7 in (120 mm) guns, in four turrets on the centre line.

[7] The accumulation of mechanical faults, fuel depletion and the enervating effect of the climate exercised severe constraints on the operations of the Red Sea Flotilla.

The Regia Aeronautica (Italian Royal Air Force) commenced operations over the Red Sea and on 11 June a Savoia-Marchetti SM.81 flew a reconnaissance sortie.

[9] On 16 June, the Italian submarine Galileo Galilei sank the Norwegian tanker James Stove (8,215 gross register ton [GRT]), sailing independently about 12 nmi (22 km; 14 mi) south of Aden.

[10] On 19 June, Hobart sent its Walrus amphibian to bomb an Italian wireless station on Centre Peak Island between Massawa and the Arabian coast.

The SM.81 was damaged hit an island trying to force land, bounced into the air and flew on at wave top height, with the Wellesley flying above and to one side for its gunners to keep firing.

[14] Convoy BN 4 was spotted by air reconnaissance and on the night of 5/6 September, Cesare Battisti, Daniele Manin and Nazario Sauro sailed.

MV Bhima (5,280 GRT) had straggled and was damaged in an Italian air attack, one man was killed; the ship was towed to Aden and beached for repairs.

[17] Convoy BN 7 was northbound through the Red Sea and consisted of 32 British, Norwegian, French, Greek and Turkish merchant ships.

[8][b] Convoy BN 7 was nearing Perim, a volcanic island off the south-west coast of Yemen in the Bab-el-Mandeb, on the afternoon of 19 October, when an aircraft dropped four bombs close astern of one of the merchantmen.

The convoy was about 35 nmi (65 km; 40 mi) north-north-west of Jabal al-Tair Island at 02:19 on 21 October, when Leander sighted two patches of smoke bearing north.

[20] Auckland reported two destroyers 4 nmi (7.4 km; 4.6 mi) off and Leander altered course to intercept, the captain assuming that they would run for home through the South Massawa Channel.

[21] Sauro and Nullo had been manoeuvring to a more favourable position after receiving the sighting report from Pantera, turned towards the convoy and spotted Leander at 01:48 (21 October).

Kimberley had lost water in its boilers and Leander sent a boat with three shipwrights and an engine-room artificer; a wounded rating was transferred to the cruiser for medical attention.

Despite agent reports and sightings by the Regia Aeronautica, Italian submarines and ships had frequently failed to make contact with the convoys; only six air attacks were achieved in October and none after 4 November.

[29] During the attack on Convoy BN 7, the British found that they were at a disadvantage in night fighting as they were temporarily blinded by the flash of their guns, while the Italian ships used flash-less cordite and had good tracer ammunition.

[30] Of the 120 crew of Nullo, Borsini declined to abandon ship and when his assistant, Seaman Vincenzo Ciaravolo, realised he jumped from his lifeboat to accompany his captain and both were drowned.