Why the Royal Navy committed a powerful hunting force

The deployed force was unusually strong for a routine patrol against ore traffic: HMS Arethusa, four Tribal-class destroyers, and the I-class destroyers Intrepid and Ivanhoe serving as minelayers. An influenza outbreak had also led to extra personnel arriving from HMS Aurora, helping provide boarding parties despite sick crews. Intelligence from intercepts and sailors released by Admiral Graf Spee gave Britain a likely route and timetable for Altmark. The destroyer flotilla leader held command instead of the cruiser captain. The force's unusual size and command arrangement suggest that Altmark was an intended target behind the nominal ore-shipping patrol. Preventing a propaganda victory from the prisoners' arrival in Germany helps explain the scale of the commitment.