SS Tembien

[1] Tembien left Trapani, Italy, for Tripoli, Libya on 16 February 1942, escorted by the destroyer Saetta and arriving two days later.

This journey went un-hindered by the Allies as Enigma decryptions (so-called Ultra intelligence) recorded only a convoy of unknown composition, and details of its position arrived too late for an attack to be made.

[2] On 27 February 1942 Tembien, having left Tripoli, was sailing around 25 miles (40 km) to the west of the city, carrying 468 Allied prisoners of war from the North African campaign to Italy.

Two of Wanklyn's torpedoes struck the Tembien, causing her to sink and leading to the deaths of between 390 and 419 prisoners, 68 Italian crew members and 10 German guards.

[5] One possibility is that to allow all prisoner-of-war ships safe passage on the basis of decrypted information would have alerted the Axis powers that the British had broken the Enigma codes.