In fact, Göring had already ordered a few raids over Britain. Hajo Herrmann and KG 4, for example, had been dropping mines at the mouths of British harbours, while raiders had attacked airfields in Britain for three nights from 5 June, then industrial works for two more nights on 18 and 19 June. None of these light attacks had caused much damage, however. Certainly there had been no sustained effort, no wholehearted commitment, against Britain yet.
That was fine by Göring, who felt no burning sense of urgency to launch an all-out air assault on Britain. Like the Führer, he remained convinced that the British would see the light and sue for peace. In any case, following the end in France, there was much reorganization to be done.
Units needed to move up to the north-east, others needed to be rested. Supply chains needed to be established. Some of the losses suffered since 10 May had to be made good. Aircraft needed to be repaired and new models sent to their Gruppen. Should Britain insist on fighting on, then at least his Luftflotten would have built up their strength ready to unleash the hammer blow.
Air Chief Marshal Dowding was also continuing to make good use of the respite, for with the rapidly changing situation since 10 May his defensive system had needed urgent and considerable modifications. This system, so carefully developed and refined ever since Dowding became C-in-C of Fighter Command, had become a highly efficient and effective means of co-ordinating all his resources to their best capabilities. A key facet was the radar chain, but this was only one cog in the system. Chain Home and Chain Home Low were an effective demonstration of the benefit of new science but it was when they were linked to other cogs that their benefit really came to the fore.
One of these other cogs was the Royal Observer Corps and its vast telephone network. Its roots went back to 1917, during the German Zeppelin and Gotha raids. Major-General Ashmore set up a warning system for London using various defence units which reported through a new telephone network to an Operations Room at Ashmore’s headquarters. A few years after the war, Ashmore refined the system again, using volunteer civilians to man a series of experimental posts between Tonbridge and Romney Marsh in Kent. These proved successful, so he was authorized to set up an observer network that covered all of Kent and Sussex. Dividing the two counties into a number of zones, each zone was then given a number of observer posts, each connected by a direct telephone line to an observer centre, which was in turn linked to Air Defence HQ. Once again, Ashmore’s system worked well, so the Home Office authorized the establishment of the Observer Corps, which gradually grew and grew into a network of ‘Groups’, which were then attached to nearby fighter stations. Thus No. 1 Group, based in Maidstone, for example, was attached to Biggin Hill.
By the summer of 1939, there were still gaps in the Observer coverage, in north-west Scotland, west Wales and Cornwall, but there were now more than 1,000 posts and some 30,000 observers, all managed by the police. Observers remained volunteers and trained on evenings and at weekends, but from 24 August, when the Corps was mobilized, they were expected to carry out round-the-clock manning of posts. They also came under the direct control and administration of the Air Ministry. Pay was introduced, although many never claimed their hourly rate, but apart from their tin helmets they were not issued with any uniform.
Each area was divided into groups. Within each group were a number of posts, whose observation area was a concentric ring around the post, and which overlapped with neighbours so that every part of the sky above was covered. These would be given a letter and a number dependent on where they were on the group grid, such as ‘R2’ or ‘J3’, for example. There were usually thirty to thirty-four posts in a group, each manned by around fourteen to twenty observers. Each post consisted of a hut, in which there were a telephone, binoculars, logbook, tea-making facilities and a pantograph that looked a bit like a giant sextant. With a height bar and sighting arm, it also had a device for correcting height estimates and was mounted on a gridded circular map of ten miles radius. When an aircraft was sighted, the observer manning the pantograph made his calculation, then another of the observers rang through to the group centre. Plots were then followed at the group centre and forwarded on to RAF Operations Rooms. Where radar warned of aircraft approaching Britain, the Observer Corps provided information inland, as well as a back-up to what was being provided by CH and CHL. It was also incredibly quick. By breaking the system down to area, group and post, and by having different people concentrating on different tasks, the Observer Corps network could manage over a million reports during a twenty-four-hour period, each of which could reach Fighter Command Headquarters in under forty seconds.
Information from the radar chain and the Observer Corps was all very well, but useless unless the controllers on the ground were able to use the information to direct fighters towards their targets. Radio telegraphy – R/T – was standard in most aircraft at this time and allowed pilots to communicate with each other once airborne. What had not been common practice, however, was for pilots to be able to communicate with ground controllers, or for ground controllers to be able to direct (or ‘vector’ as it was termed) fighters towards targets from a control room – but this is precisely what Dowding introduced. Not only did Fighter Command pilots have radios that enabled them to listen to ground controllers, but there were also networks of antennae radio receivers on the ground that picked up transmissions from the pilot. Cables ran from these antennae to the control room, where, on a cathode ray tube screen, the direction of the transmission could be picked up. With the receivers at the centre of the screen, a line would light up from the transmissions from the pilot, which would then indicate what bearing he was on. This was called High Frequency Direction Finding, or HF/DF (pronounced ‘huff-duff’), while the automatic transmissions were christened ‘Pip-Squeak’.
With information on enemy aircraft’s position from radar and the Observer Corps, it was then a case of applying simple trigonometry. Drawing a line from the enemy to the fighters and making this the long base of an isosceles triangle, the fighter would then be vectored along an angle that was the same as that of the bomber. Where the two equal angles met to form the apex of the triangle would be where the two would meet, known as the interception point. If the bombers changed course, a new triangle would be visualized and if the fighter reached the apex before the bomber, he could circle and wait. A further refinement was the ‘Pip-Squeak’ system, by which a pilot’s radio gave off transmissions automatically for fourteen seconds in every minute. In the control room there would be a clock with its face divided into four coloured quarters, with a hand that rotated once a minute. Four aircraft could thus be controlled in rotation, each pilot being told the quarter in which he was to set his control. The code word for Pip-Squeak was ‘cockerel’; if a pilot forgot to switch it on, as often was the case, the controller could ask, ‘Is the cockerel crowing?’ It was simple but ingenious.
The final cog was the telephone network, which was run and maintained by the General Post Office, the GPO, then still part of the Government. GPO engineers were responsible for laying vast numbers of extra lines between 1937 and 1940. Most RDF stations, for example, were built on comparatively remote farmland, which provided a big logistical challenge. At each, two lines were needed for signalling between stations and the appropriate fighter group headquarters Filter Room. These also needed to be taken through different routes as an insurance against damage. Another line was needed for general operational control, while a further two lines were needed for communicating between neighbouring stations – thus each station needed five new and separate lines in all. At Bentley Priory, all lines went through the Stanmore exchange at the bottom of the hill, but, in case of damage there, an entire duplicate set of lines was built through to the Bushey exchange to the north.
In addition to this incredible and complex amount of engineering work to and from fighter stations, radar stations, Observer posts and so on, the GPO also created a separate network, authorized by the Treasury, called the Defe
nce Teleprinter Network (DTN), as a back-up and an extra means of confirming signals. This linked and served all three home RAF commands, but was still run by the GPO, and maintained by its specially created War Group.
Clever science, ingenuity, common sense and the dedication of thousands of volunteers ensured that Fighter Command could call on a series of invaluable cogs in its defensive system. However, bringing all these together effectively and efficiently into a smooth and reliable machine was of vital importance were Fighter Command to reap the maximum benefit from what each of these strands had to offer. Fortunately, Dowding had managed exactly that.
Centralization and standardization were the key. Fighter Command was divided into operational groups, each of which had its own headquarters and Operations Room. The Groups were then divided into sectors, which were given a code letter. Each sector contained a principal fighter station and sector headquarters with its own Operations Room. Linked to this were the sector’s direction-finding stations. Also within each sector were other satellite airfields. For example, Duxford was a sector station, and nearby Fowlmere was a satellite. All Operations Rooms, whether sector, Group, Fighter HQ, or Observer Corps centre, looked the same. In the centre of the room was a large plotting table with a map of Britain, on which were all the sectors and Observer Corps zones. It was large enough for anyone looking at it to see at a glance precisely what was going on. Around the table were the plotters, each equipped with telephone headsets and a croupier’s rake. As a call came through, the information would be plotted on the map, with the marker pointing in the direction the aircraft were heading. Rectangular coloured counters were added to show height, size and whether they were bombers or fighters. RAF plotters were WAAFs, from the Women’s Auxiliary Air Force, and were popularly known as the ‘Beauty Chorus’.
Overlooking the plotting table on a raised dais were the men who would use the information being collated in front of them. At a sector station, there were usually about eight such people, with the Senior Controller at the centre, controlling the squadrons in his sector. Next to him were the Assistant Controller, and then the two Deputy Controllers. Either side of them was ‘Ops A’, who was in permanent contact with Group, and ‘Ops B’, whose job it was to ring through to the squadron dispersal and scramble the pilots. On the wall opposite the controllers would be the five-minute colour change clock. Each five-minute section of the clock was coded red, yellow or blue. When a plot came through, it was given the colour indicated by the minute hand at the time of its arrival. There were also a weather board, a list of barrage balloon squadrons and their heights, and a series of panels, at the top of which were written the Fighter Command squadrons in each, and beneath them their state of readiness, such as ‘available’, ‘in position’ or ‘landing and refuelling’. The relevant state would be illuminated by a maximum of four lightbulbs, each reflecting the relevant colour of each squadron section, red, blue, yellow and green. Only when ‘enemy sighted’ was lit up would the bulbs all be coloured red. These state boards were known as ‘totes’ because they looked rather like the lists of horses and odds displayed at a race meeting. Below these there was also a list of the pilots and aircraft available to each squadron, which would be updated first and last thing each day. Thus with one glance a controller had a mass of information about the current state of play at his fingertips.
Dowding had also issued a series of very simple code words for various orders; they could be easily memorized and rarely misheard or mistaken for something else. Thus ‘scramble’ meant take off as soon as possible, ‘orbit’ to circle, ‘vector 230’ to fly on a course of 230 degrees; ‘angels’ meant height – ‘angels 15’ stood for 15,000 feet; ‘bandits’ was the code for enemy aircraft. It was simple and it was standardized.
The hub of this network – the nerve centre – was Fighter Command Headquarters at Bentley Priory. The pièce de résistance, however, was the Filter Room, which, since March, had been housed in a concrete bunker below the priory itself. All radar plots were received here, with a filter officer for each CH and CHL station. Information was checked and assessed and cross-referenced with other known flights. Another canny invention was Identification Friend or Foe (IFF), which was a small transmitter in all RAF aircraft that gave a distinctive blip if they flew near the coast and were picked up by radar. When it was not clear, plots would be labelled ‘X’. This was the filtering process. Once this was done – and filter officers were highly trained to do this task quickly and accurately – the plot was given a number and passed to the Command Operations Room in the bunker next door, and simultaneously to the Group controllers, who then passed them on to the relevant sector stations. Sector stations then forwarded details of the plot back to Observer centres.
With all the different links in the chain and the mass of different telephone lines relaying information, any lesser system would have created utter chaos and mayhem. It worked, however, because in essence it was very simple and everyone knew precisely what their job was and did not deviate from that. Only at Bentley Priory was there a complete overview of what was going on, but Dowding did not then interfere with the operational and tactical control of his Fighter Groups. The Group Commander and his controllers decided what sectors and squadrons to use and when. Similarly, it was then left to the sector controllers to bring their squadrons into contact with the enemy. In Fighter Command there was no von Rundstedt sticking his oar in.
But that was not all Dowding had at his disposal. Directly under him was AA Command with its anti-aircraft guns and searchlights, although the number of guns available was woeful. Lieutenant-General Pile, C-in-C AA Command, had only 1,204 heavy ack-ack guns and a pitiful 581 light guns, as opposed to the 2,232 and 1,860 that it was agreed he should have. In other words, there were only half and one third the number of guns considered necessary – and many of these were obsolete. This was not good. Heavy defence of aircraft factories was necessary, but then airfields, ports and naval bases also needed defending, as did numerous other industrial plants. The buck supposedly stopped with Dowding, but, as he was well aware, such decisions were beyond his realm of experience and he found himself spending far too much time discussing which of these precious guns should go where. To get around this, he formed a committee representing the various different interests and let them thrash it out between themselves. It also helped that he had an excellent working relationship with General Pile, and whatever dispositions of guns there were could be immediately relayed to Groups and sectors and thus to the fighters in the sky.
He also had some 1,500 barrage balloons in Balloon Command under his orders, as well as control of the Air Raid Warning System, which was operated from Bentley Priory. Furthermore, he benefited from whatever information could be gathered by Air Intelligence and, indeed, from other intelligence branches via the Air Ministry. Permanently at Fighter Command HQ were General Pile as well as liaison officers from the other commands, from the Admiralty, and also the heads of the Observer Corps and Balloon Command. Each had his place on the dais in the Operations Room with a direct line to his organization.
There were flaws in the system. Neither radar nor the Observer Corps could accurately assess the height of an incoming raid – although they got it right more often than not – and with the exception of Bentley Priory not a single Operations Room was even remotely bomb-proof. Yet in all other respects it was genius. Dowding had been given truly awesome responsibilities, yet he had achieved what so few leaders ever properly manage, and that was the ability to delegate – to give each person in the chain a clearly defined role and then let them get on with it. And it was remarkably flexible too. Because of the standardization, squadrons could be added or removed from various sectors, sent into different Groups, and the system remained exactly the same. This allowed Dowding to rotate his squadrons; it also meant that if he needed to reinforce a particular Group, he could do so easily. The system also ensured that his squadrons did not waste time or energy with fruitless standing patrols
. They were trained to be airborne in a matter of minutes, and could now be vectored towards the enemy as and when it arrived. Of course, it would never run 100 per cent smoothly all the time, but it was still the most sophisticated and comprehensive defence system in the world at the time.
By the beginning of July, Fighter Command was sufficiently ready to face the Luftwaffe. Dowding would have liked more aircraft and more pilots, but new machines and men were arriving with every passing day. His defence system was established, those under his command knew what they had to do, and his squadrons had benefited from the pause in the Luftwaffe’s attention.
Every man was now waiting for Göring’s air fleets to attack. Whether their preparations had been enough, however, only time would tell…
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Trouble at Sea: Part 2
ON 3 JULY, THE HARTLEPOOL, a 5,500-ton freighter, inched its way out of Southend-on-Sea. It was one of fifty-three slow, chugging merchant ships that made up convoy OA178. ‘OA’ for ‘Outward Bound, Route A’; this was a large transatlantic convoy heading to Sydney, Nova Scotia. Hartlepool was near the front of the convoy, each of the ships progressing down the Thames estuary in a single line, one after the other. Nearly an hour later, Captain William Rogerson, looking back from the bridge, still could not see the tail of this long line of ships.
The Battle of Britain Page 43