It has been noted already, in chapter two, that the German Government did not respond positively to Franco's later June offer to go to war on the Axis side. Berlin had preferred to wait upon events, to see if Spanish services could really be of use against Britain before any Nazi effort was made to purchase them. However, Britain's stubborn refusal to lay down its arms, and the formidable resistance offered by the Royal Air Force to Göring's attempts to bomb the British into submission, or to establish the Luftwaffe's mastery in their skies which would have enabled the Germans to undertake Operation ‘Sea Lion’, caused Nazi grand strategists to indulge in some agonising reappraisals, in the early autumn of 1940. German army and navy advocates of a peripheral strategy against Britain, as an alternative to the perilous Channel crossing and frontal assault on the English mainland, emphasised the advantages of attacking British imperial outposts, particularly Gibraltar and the Suez Canal, in conjunction with the Spaniards and the Italians. Such a Mediterranean campaign could turn that sea into an Axis lake, ensure peace and quiet in the Balkans, secure the Middle East and its raw materials for Britain's enemies, and open up new offensive opportunities in the Atlantic and Central Asia.