While the airmen were puzzling over the packages, the ground crew – the ‘erks’, as they were affectionately known – were busy checking the aircraft. After a while the airmen climbed into the machines to join them. No matter how curious they might be about the enigmatic parcels, there was work to be done on the plane – equipment to be checked, mechanisms to be tested. This was the machinery on which their lives depended, and few crews neglected their preparations for a night on ops. The gunners would oil their guns, and perhaps realign them so that they converged at the right point. The bomb-aimer would check his instruments, as would the wireless operator and the navigator. Then, perhaps, the pilot and the flight engineer would take the machine up for a quick air test, to make sure it was flying smoothly, before returning to base for lunch and the long, slow wait till dusk.

That afternoon was a nervous one for many. Until briefing in the evening there was nothing to do but hang around and try not to think of the night that lay ahead. They were barred from leaving the base, so there was no chance of distracting themselves with a trip to the local village. Instead they would take to their quarters and try to catch an hour’s sleep, or lie on the grass in the bright summer sunshine, gazing across the airfield at the petrol bowsers pumping fuel into their aircraft, at the erks cycling round the perimeter track, or the WAAF drivers bringing bomb trains to the hangars. Many airmen describe feeling strangely divorced from all the purposeful activity that surrounded them during the long hours of the afternoon, as if it had nothing whatsoever to do with them. And yet, subconsciously, they were aware that it had everything to do with them – that they, indeed, were the reason for it. It was impossible to forget that in a few hours’ time they would be taking off in those huge, forbidding machines, and the peaceful English afternoon would be transformed to a nightmare of flak and fighters in the skies over Germany.

Experienced airmen would try to avoid thinking of what lay ahead, and distract themselves with games of chess or football, or by laughing at the latest buffoonery of Pilot Officer Prune in Tee Emmagazine. It was best not to think of all the narrow escapes of previous sorties over the cauldron of Essen and the other cities of the Ruhr valley. And yet the thought inevitably surfaced: perhaps tonight their luck would run out. Bomber Command losses were running at almost five per cent at the time – in other words, one in every twenty planes on any given night would not come back. A standard tour was thirty operations. It did not take a mathematician to work out that the odds of finishing it alive were stacked against any airman.

For inexperienced crews the prospects were even worse: there was always a far higher proportion of losses among those who were on one of their first five operations. Brand new crews, or ‘sprogs’, as they were known, would have felt especially nervous about what lay ahead. All the training in the world could not prepare a young man for the stress of combat, and many were worried about how they might react. If a pilot panicked or a gunner froze at the wrong moment, it might mean not only his own death but that of his crewmates. It is important to remember that many airmen were still in their teens when they began flying – the average age of a new recruit into the training schools was twenty one – and many viewed their first operation as an important rite of passage into manhood. ³At this stage of the war they were aware that a significant number would be blown out of the sky.

At last, around five o’clock, the men were called. The crews would filter into the briefing room and take their places in the rows of chairs, some talking and joking to take their minds off the night ahead, but the majority gazing quietly at the board at the end of the room, curious about what lay beneath the sheet that covered it. Once the door was closed behind them there would be a roll-call, and then the officer in charge of operations – usually one of the flight commanders, but occasionally the commanding officer (CO) – would pull down the cover to reveal the target map. Across the room men would crane forward to see where the red line of ribbon on the map led to. For the benefit of those at the back, the officer would declare, in a loud, clear voice, ‘Your target for tonight, gentlemen, is Hamburg.’

For many crews there was a sense of at least partial relief on seeing the target. After numerous flights to the Ruhr, where the defences were second only to those at Berlin, it would make a welcome change: the flight to Hamburg was mostly over the North Sea, so there was less chance of being caught by flak on the journeys in and out. On the other hand, in some squadrons Hamburg was as notorious as anything the Ruhr could offer. In 57 Squadron, for example, Hamburg had a particularly bad reputation. They had not attacked the city since March, when the CO, Freddie Hop-croft, and his crew had almost been killed. Ever since then the CO had briefed other targets with the words, ‘Now, boys, the defences are nothing like as good as Hamburg’s, so you should be all right.’ After several months of this the strengths of the Hamburg defences had gained near-mythical status, and to learn that they were flying to the city naturally filled 57 Squadron crews with trepidation. ⁴

After a general briefing by the CO, describing their route, the time of attack and so on, a variety of other officers would take the stage. The meteorological officer would advise on weather conditions over the target and on the journey in. The armament officer would detail bomb loads, and the signals officer would brief them on what radio countermeasures they would use. Tonight, for the first time, the ground stations would be transmitting average windspeeds (or ‘Zephyrs’, as they were codenamed) to all the crews at regular intervals to help with navigation.

Eventually the intelligence officer took the stage. He commanded the men’s attention far better than the others because he told them where the danger spots would be on the outward flight and why they were going after this particular target. Hamburg, he explained, was not only a major hub of manufacturing, it was also Germany’s main centre of submarine production. If they could knock the city out of the war it would deal a blow not only to the Germans at home but to their effort in the battle of the Atlantic.

That day, however, the intelligence officer had something else to tell them. Once he had finished his normal spiel, he explained the secret behind the brown-paper packages that the crews had seen being loaded into the aircraft earlier. The silvery strips inside the parcels were called Window, he said, and they were a new and simple measure designed to confuse German radar defences.

‘You will already have been told how to drop Window,’ the intelligence officer continued; ‘it has been worked out as carefully as possible to give you maximum protection, but there are two points which I want to emphasize strongly. Firstly, the benefit of Window is a communal one: the Window which protects you is not so much that which you drop yourself as that which is already in the air dropped by an aircraft ahead. To obtain full advantage, it is therefore necessary to fly in a concentrated stream along the ordered route.

‘Secondly, the task of discharging the packets of Window will not be an easy one. You are hampered by your oxygen tube, intercom connections, the darkness and the general difficulties of physical effort at high altitudes. Despite these hardships, it is essential that the correct quantities of Window are discharged at the correct time intervals.’

He went on to explain that Window was considered so important that the Air Ministry was already developing machines to ensure a steady flow from the aircraft. In the meantime, however, it was up to the airmen themselves to maintain a ‘machine-like regularity’ when dropping the bundles down the flare chute.