Inferno - Max Hastings [234]
On 1 July, when the Germans attacked again, they were repulsed in what became known as the first battle of El Alamein. In the encounters which followed neither side gained a decisive advantage. But what mattered was that Rommel was denied a breakthrough—although, given the opposing forces’ respective strengths and detailed Allied foreknowledge of German intentions, it would have been disgraceful had he achieved one. In the first days of August Churchill arrived in Cairo with Gen. Alan Brooke, to see for himself how things stood. He sacked Auchinleck, who was replaced as Eighth Army commander by Brooke’s nominee, Lt. Gen. Sir Bernard Montgomery, and as Middle East C-in-C by Gen. Sir Harold Alexander. A month later, on 30 August, Rommel attacked at Alam Halfa. Montgomery, provided by Ultra with full details of German plans, drove him back. The general then addressed himself to training Britain’s troops for his own offensive. He had two critical advantages: large U.S. tank reinforcements were arriving and the Desert Air Force had gained dominance of the sky.
THE VOLUME of Ultra intelligence was now increasing dramatically, with critical influence in every theatre. In earlier years, decrypts were priceless, especially to the naval war, but their flow was erratic. From mid-1942 onwards, with a few important breaks, the Allies became privy to much of their enemies’ signal traffic; the penetration of German and Japanese ciphers made a massive contribution to victory. Beyond the achievements of British and American decrypters, it was a secondary miracle that the Axis powers never seriously suspected that their most secret communications were being accessed by the enemy. Not all important traffic was read all the time: Axis telephone landlines, always the link of choice where available, remained secure. The quality of Allied analysis and exploitation varied in accordance with the prejudices of field commanders and their intelligence chiefs. For instance, Ultra would later reveal the December 1944 German armoured buildup in the Ardennes, but staffs failed to draw appropriate conclusions about an impending offensive. Knowing the enemy’s hand did not of itself diminish the strength of his cards, and provided no guarantee of success in clashes between armies and fleets. But Ultra revealed to the Allies more about what the other side was doing and planning than had been vouchsafed to any previous combatants in history.
The Ultra achievement owed much to three Polish mathematicians, led by Marian Rejewski, who conducted critical early work on the German Enigma code machine between 1932 and 1939, after acquiring a commercial example of the ciphering device. The French assisted, providing the Poles with a list of 1931 Wehrmacht keys, acquired from a German source. Ironically, through Rejewski served with the Polish army in Britain between 1943 and 1945, he was never told of the rich fruits of his own pioneering achievements. In 1939 the Poles presented both the British and the French with reconstructed Enigma machines. The following year, these enabled the British Code and Cypher School at Bletchley Park to begin to break some German and Italian messages. At intervals thereafter, captures at sea of further Enigmas and monthly settings lists reinforced Bletchley’s armoury of knowledge.
Ultra was a collective Allied designation for a large variety of Axis keys, more than 200 by 1945, some of which proved slow to surrender their secrets. Luftwaffe signals were broken first, towards the end of May 1940, followed by army and navy traffic. In 1941, a substantial volume of Wehrmacht messages were being read and their contents passed to Allied field commanders with an average delay of six hours. This proved too slow to influence tactical decisions in ground fighting. It became progressively understood that Ultra could be used most effectively to guide strategy, as it was during the summer 1942 Alamein battles.
Allied handling of Ultra intelligence became superbly sophisticated, with information passed to commanders by locally deployed Special