Tobruk fell on 21 June and a week later two British corps were shattered at Mersa Matruh. There was a disorganised retreat east to the Nile Delta; the Royal Navy left the harbour at Alexandria causing ‘panique’ in the city’s high society. Privileged and well-connected womenfolk were evacuated from Cairo to Palestine, and everyone else had contingency plans to evade German occupation. So much paperwork was torched in Cairo during what became known as ‘The Flap’ that 1 July 1942 was dubbed ‘Ash Wednesday’. You could buy peanuts in twists of paper headed ‘MOST SECRET’. They had gone up unburnt in the hot smoke and then fluttered down all over Cairo.
When all seemed lost, Auchinleck boldly took personal command of the Eighth Army. He reorganised them into battle groups, and with his back to the Nile, halted Rommel’s advance at the First Battle of El Alamein in July 1942. Dudley Clarke’s deception plan for 1st Alamein was called OPERATION SENTINEL. As usual it drew on his well-stocked chest of ‘notional’ forces. ‘A’ Force whirled up a khamsin of camouflage and deception to buy the British some time. SENTINEL managed to persuade German Intelligence that there was an army camped in the sandhills before them. Through the dust of bogus activity the Germans seemed to glimpse at least two motorised divisions and a light armoured brigade. Faced by such a force and with his supply lines stretched, Rommel could not press forward. Auchinleck did not win a decisive victory, but he held the pass.
British security had to grow tighter now. The British captured Rommel’s radio monitoring station ‘Schildkrote’ (Tortoise) at Tel al Aysa the same month, and discovered that Rommel’s SIGINT unit (621st Signals Battalion) had learned about British plans and the Allied order of battle from careless wireless traffic. The Germans had also broken the US military attaché’s code. Two German signallers were both found to possess copies of Daphne du Maurier’s best-selling novel Rebecca in English, although they didn’t speak a word of the language. The books were in fact being used for coding and decoding messages from two German spies who had been working in Cairo with the Egyptian Army officer Anwar El Sadat. Driven across the desert from Rommel’s HQ in May by the explorer Laszlo Almasy (fictionalised in Michael Ondaatje’s The English Patient), the spies, code-named kondor, now lived on a sleazy houseboat near Cairo’s Zamalek Bridge with a transmitting wireless hidden inside a large radiogram. They had been spending Abwehr-forged English £5 notes in Shepheard’s Hotel, Groppi’s, the Turf Club and the Kit Kat Club. Sansom of Field Security managed to track them down and in a raid on their houseboat at 2 a.m. on 25 July, the agents failed to throw their matching copy of Rebecca, with an already encoded message, into the Nile. The British then turned this to their own advantage by using the spies’ radio to send false messages to Rommel as if from kondor, expressing ‘British fears’ of an attack on the vulnerable Alam el Halfa Ridge (which in fact was heavily defended). The false messages were accompanied by a classic haversack ruse. A bloodstained British armoured car was left half wrecked and abandoned on the edge of a minefield for the Germans to find. It yielded for the eyes of enemy intelligence a map deceptively marked up for armoured vehicles: hard ground was deemed ‘impassable’ while the soft sift that drained three times as much precious fuel was indicated as ‘good going’.