Serrano Suñer's trip to Obersalzberg in November 1940, and the way in which he drew the Germans' attention, then, to the economic obstacles in the way of immediate Spanish entry into the war, have been noted in the previous chapter. However, on 28–9 November, Franco's willingness to initiate and accelerate preparations for his war effort on the Axis side was communicated to Berlin. This news was welcome to Berlin as Hitler had by then decided upon the absolute necessity of an early Spanish entry into the war. For only by capturing Gibraltar and sealing off the Mediterranean could he eliminate the threat of the French colonies in North Africa defecting to the British, and relieve the dangerous situation in the Eastern Mediterranean and Balkans, all stemming from the Italian debãcle in Greece. Operation ‘Felix’ to capture Gibraltar and close the Straits, whilst securing the Iberian Peninsula against British retaliation, had been long in gestation. All that was required for its implementation was Franco's formal assent to German forces crossing the Spanish frontier, on 10 January 1941, with the attack on Gibraltar to commence around 4 February. Hitler sent Admiral Wilhelm Canaris, Chief of the Abwehr, and an expert on Spanish affairs, to obtain the Caudillo's agreement to this German timetable for an offensive against the Rock.