the ground and destroyed and of fuel were set alight, four Africans were killed and eleven injured fighting the fire. War at sea, 1940 The approaches to the Red Sea through the Gulf of Aden and the Strait (Gate of Tears) is wide. With the Italy declaration of war on 10 June and the loss of French naval support in the Mediterranean after the Armistice, the Red Sea passage to Suez became the main British sea route to the Middle East. South of Suez the British held Port Sudan, about halfway down on the Sudan coast and the base at Aden, east of Bab-el-Mandeb on the Arabian Peninsula. The principal Italian naval force ( [Rear-Admiral] Mario Bonetti) was based at Massawa in Eritrea, about north of the Bab-el-Mandeb, well placed for the Red Sea Flotilla to attack Allied convoys. British code-breakers of the Government Code and Cypher School (GC&CS) at Bletchley Park in England, deciphered Italian orders of 19 May, coded using C38m machines, secretly to mobilise the army and air force in East Africa. Merchant traffic was stopped by the British on 24 May, pending the introduction of a convoy system. The Red Sea Force (Senior Naval Officer Red Sea, Rear-Admiral Murray), operational at Aden since April with the light cruisers and HMAS Hobart (Liverpool was replaced by ), was reinforced by the anti-aircraft cruiser , which sailed south with Convoy BS 4, the 28th Destroyer Flotilla comprising , Kimberley, and and three sloops from the Mediterranean. The force was to conduct a blockade Italian East Africa (Operation Begum), attack the Red Sea Flotilla and protect the sea lanes from Aden to Suez. On 6 June, the Azio-class minelayer Ostia used 470 mines to lay eight barrages off Massawa and the destroyer Pantera dropped 110 mines in two barrages off Assab the day after. When Italy declared war on 10 June, Galileo Ferraris sailed for French Somaliland (Djibouti), Galileo Galilei to Aden, Galvani to the Gulf of Oman and Mecallé to Port Sudan. On 14 June Torricelli put to sea to relieve Galileo Ferraris whose crew had been incapacitated by chloromethane poisoning from the refrigeration system. The crew of Macallé was also afflicted; the boat was run aground and lost on 15 June. On 18 June, Galileo Galilei boarded and released the neutral Yugoslav steamship Dravo and the next day engaged the armed trawler off Aden. All but one