An oft-asked question in debate is 'what single factor contributed more than any other to Britain prevailing in 1940?'
Some say radar; yes, very important.
Some say 100 octane fuel from the United States; certainly gave our aircraft an advantage.
Some say the Observer Corps; vital information, no doubt.
And, of course, some will say the pure skill and courage of The Few; without question, yes.
But if you were to ask me what was the 'battle-winning' weapon that Britain deployed in 1940? It was the Dowding System.
'Not fair!' I hear you cry; 'The Dowding System includes Radar, the Observer Corps and our Pilots!'
Quite right, and I suppose that is my point. If we examine any of these in isolation, we truly understand the significance of the world's first Integrated Air Defence System (IADS).
Radar (Chain Home and Chain Home Low)
As Laurence Olivier said in the 1969 movie while playing ACM Hugh Dowding: 'Radar is vital, but it won't shoot down aircraft.'
Now, I'm not sure if Dowding ever said these exact words, but as the architect of the system that bore his name he clearly understood the utility of radar in exactly these terms.
Chain Home provided crucial information regarding the size, position and altitude of enemy raids, but that information was useless if not placed quickly into the hands of those who commanded squadrons. Every minute lost in passing along information equated to thousands of feet for Spitfires and Hurricanes.
Oh, and Chain Home could only 'look' out to sea. That meant that once a Luftwaffe raid crossed the coast, it was free to roam Britain undetected, except for the assistance of:
The Observer Corps
This is probably one of the most iconic images from 1940, but the importance of what it illustrates may not be obvious to those unfamiliar with the Dowding System.
Two eyes and a pair of binoculars plugged the vital gap that appeared once the enemy crossed the coast and moved beyond the sight of the Chain Home network. The final updates needed to ensure a successful interception were often provided by the Observer Corps, rather than their radar operator colleagues. As was the case with Chain Home, the speed at which this information could be passed to the squadrons was the critical factor.
It was the grit and determination of RAF pilots that ultimately got the job done, but how would the Battle have looked without the timely passing of that vital information from Chain Home or the Observer Corps?
There would have been little option for Fighter Command other than to mount standing patrols. Using aircraft in this way would have been tiring for pilots and ground crew alike, not to mention risking that at any moment an airfield might be undefended when the Luftwaffe came calling. Imagine patrolling for an hour, nervous at the prospect of battle, only to be called home and find your station under blistering attack. 'Forewarned is forearmed'.
Perhaps with a decrease in interceptions there would have been fewer losses among RAF pilots, but this would not have translated into success in the Battle. Fewer interceptions would have also meant greater loss of life on the ground as Luftwaffe raids went unopposed. Ultimately, 11 Group might have been forced to abandon the south-east altogether, while the vital aircraft and ammunition manufacturing chains would have come under critical pressure.
Integrated Air Defence
And so the Dowding System ensured that the advantages of all these fighting components were combined in a way that we refer to in the modern age as a 'force multiplier'. Radar detected the targets as they approached British airspace, allowing a response to be coordinated in many cases while a raid was still assembling. The Observer Corps provided critical updates once a raid crossed the coast, and the pilots, armed with a 'recognised air picture', were able to focus their efforts precisely where the enemy were expected to appear.
What was the single component then, if any, of this system that ensured success?
The Filter Room
This facility at Fighter Command Headquarters was the 'brain' of the Dowding System, and hence the Command and Control that enabled radar, observers, plotters and pilots to work together in a coordinated way that was hitherto unheard of. Senior officers had never before had such an overview of the battlespace unfold in real time. This single installation was the most important link in the system, essentially connecting all others, and its destruction might have crippled the RAF's response for weeks.
So why did the Luftwaffe not do more to target the Dowding System?
In short, they failed to realise that such coordination existed or was even possible. For instance, targeting Chain Home radar sites was a tricky business, and Luftwaffe intelligence failed to realise that each station was a component of a larger system. The Germans expected that a radar station was responsible for command and control of local squadrons only, whereas of course as we have seen, Chain Home was merely the 'frontline' sensor network of a vast communication system passing information to all squadrons. Germany possessed her own radar technology, in some ways superior to Chain Home, but they simply could not envisage the way the British were employing it.
Had the Luftwaffe realised the advantages delivered by the Dowding System, perhaps they would have done more to target radar installations and aerodromes themselves. As we know, history took a different course, very much thanks to Hitler and Göring's hubris.
So when the debate emerges again as to which was the battle-winning component, you'll hear me once more refer to a system of systems that set the standard for modern air defence - pioneered by Air Chief Marshal H. C. T. Dowding.