Lord Trenchard Memorial Lecture 2018

calendarclock - (BST)

This year’s Lord Trenchard Memorial Lecture was delivered by Air Marshal Edward Stringer CB CBE MA BEng RAF, Director General Joint Force Development and Defence Academy, UK Ministry of Defence.



100 Years of an Independent Air Force - What have we learned, what do we teach?

In this centenary year of the Royal Air Force, the world’s oldest independent air force, Air Marshal Stringer reflected on what independent air power has achieved. He argued that in the modern environment we need to get back to educating our officer corps in the higher strategies of deterrence and containment, and to rethink doctrine not in terms of how air power contributes tactical effects on the battlefield, but on how it sets conditions - in peace and war - that might predetermine the result of, and ideally forestall the need for, actual combat.

Watch the recording

  • Having been ACAS, the Air Force’s Assistant Chief of Staff, in 2013 it fell to me to instigate the planning for RAF100 that has come to fruition this year. And I doff my cap to those who followed and had the much harder job of turning our breezy concepts into their gritty reality. But in all my imaginings I did not foresee the unique privilege of giving the Trenchard Lecture in the anniversary year. I thank you very much for the opportunity.


    The influence of Trenchard emerges most powerfully from the Celebrate heading of the RAF100 motto: Commemorate, Celebrate, Inspire.  Rightly, we have made much of the radical nature of the nascent Royal Air Force - the fundamental reimagining of the relationship between officers and other -ranks, the social mobility enshrined in the apprentice system and the crossover with the RAF College.  Much of this has a huge contemporary resonance and it is right that this should be used to inspire the next generation…


    But it is in the operational realm that I want to extrapolate from Trenchard’s legacy.  While we have commemorated and celebrated many of the RAF’s operational achievements, I have had a nagging internal voice pestering me that we might also have missed a trick.  Undoubtedly as inspiring and engaging as the stories of individual and collective skill and daring are - the waging of the Battle of Britain and the elan of the Dambuster’s raid - they don’t explain the contribution of an independent air force per se.  And, of course, it was Trenchard who was the first commander, in May 1918, of the RAF’s Independent Force, set up to apply Air Power across the front lines, directly against the enemy, and independent of the activities of the sister services.


    It is this simple idea that causes controversy even unto today.  Come any Defence Review, one can set one’s clock by the letter appearing in the Daily Telegraph calling for the ‘wasteful’ RAF to be split up, with the bits that support the army and Navy been handed back to them.  In checking my sources (and prejudices!) for this lecture, I came across a recent review in The Guardian of Richard Overy’s The Bombing War in which a very senior Cambridge historian had stated unequivocally that it had been shown that the correct use of air power was in direct support of the army.


    At this point let me state that this will not be a needy, defensive talk revisiting Smuts and the requirement or not for an independent air service.  I am quite confident in that argument. But that it is still live in some quarters suggests that we have not fully absorbed what an independent air force delivers in war.  Nor do I believe that even air forces themselves have fully internalised what they deliver in war, as distinct from what they do in warfare. As Mark Clodfelter, then still a serving USAF officer, put it back in 1989 in his book ‘The Limits of Air Power’: “The tremendous rush of technology…has not guaranteed military success. What it has done, however, is to create a modern vision of air power that focusses on the lethality of its weaponry rather than on that weaponry’s effectiveness as a political instrument.”


    My aim this morning is to argue three things: First, that the history of an independent air force demonstrates that it allows new ways in war, ways that have allowed the UK to achieve success at lower costs than would have previously been the case.  Second, that what one might call the UK’s Defence Polity has not necessarily absorbed that lesson, preferring instead to concentrate on how the air force contributes to warfare. And, third, that this is important as we consider how we should deal with the re-emergence of state threats in an era of permanent competition. I shall concentrate on the first comprehensive test of Trenchard’s new Service, the Second World War, as there is much contemporary research published in the last few years that usefully develops the established arguments.


    There is an irony in making a case that air forces have not, traditionally, expended as much effort thinking about the conceptual component of combat power as they have on ensuring a robust replenishment of the physical component or bolstering the moral one.  Because no one can accuse the early pioneers of lacking visionary zeal.  I shall take it as read with this audience that we are all familiar with the history of the inter-war years, in which the RAF first of all survived and then grew. We are familiar with the politics of re-armament in the light of the carnage of the trenches, and familiar with seminal air power thinking, as best embodied in Douhet’s Command of the Air of 1921 but endorsed and followed most keenly in the UK and the USA by Trenchard and Mitchell.  These have a contemporary relevance as the statements of the pioneers, and the subsequent actions of the air power commanders of World War 2, are still cited today in support of a range of arguments. 


    The most contentious, already raised tangentially, is the efficacy of the Combined Bomber Offensive of 1943-1945.  Much recent study has shed new light, but the results still need interpretation.


    A new breed of historians has looked at the politics and economics of the war effort, using evidence now available on German economic capacity and Nazi regime internal analysis of its own strength and standing with the German populace.  Adam Tooze, David Edgerton, Phillips O’Brien, Daniel Todman and Nicholas Stargardt have all written excellent works that investigate one way or another what gave the allied powers their edge.  All redevelop the theory advanced in Richard Overy’s Why The Allies Won of 1995. His outstanding, thematic distillation could be boiled down to the German forces were defeated on the ground in the East and in the air in the West.


    Phillips O’Brien takes this a step further, in 2015’s How The War was Won, looking at what the various powers spent their money on, and which operations actually led to significant materiel depletion of the enemy, and so a weakening of its power and strategic position. He argues that the US and UK’s Air and Sea power, in what he calls the Air-Sea Battle, was the significant eroder of German national fighting power and therefore the crucial factor in Germany’s defeat.  O’Brien goes as far as to suggest that no land battle was pivotal, being but an indicator of the current balance of national power.  All to some extent cite the Combined Bomber Offensive, in its direct effect on the German economy and war-fighting apparatus, and in its secondary effect of the costs and opportunity costs on Germany of defending what amounted to a second front.


    There is a counter view, and A C Grayling in Amongst The Dead Cities, and most significantly Richard Overy himself in his most recent and impressively comprehensive study, The Bombing War, judge that the Combined Bomber Offensive, and in Overy’s study strategic bombing in general, was wasteful and did not achieve what it set out to do. 


    The latter charge - of not succeeding in what it itself set out to do - is no doubt valid, as the initial claim that Bomber Forces alone could quickly bring an enemy to its knees and force it to sue for peace were always extravagant.  Nevertheless, this has the yardstick, understandably given the vociferousness of the claims and unyielding drive of the bomber bosses, especially by ACM (Bomber) Harris, …been the yardstick that has then been used to measure success or failure ever since.  Is this, though, the correct benchmark for measuring effectiveness? 


    I find myself in agreement with those reviewers of Overy’s recent work - of which I would recommend Adam Tooze in the New York Times, Tami Davis Biddle in Warfare In History, and Edward Luttwak in the London Review of Books - who are slightly baffled by the conclusions in his book given the evidence now available and the arguments he himself makes that point, perhaps, to more nuanced conclusions.  I am more swung by Overy’s previous judgements, and find the latest historical analyses of Edgerton et al compelling.


    The case I would make is that the Combined Bomber Offensive can not be removed from the overall pattern of Allied Air Campaigning, indeed from the overall approach to strategic campaigning from the allied powers, which did have a logical thread.  The CBO - which as Luttwak points out had its successes and reverses - was the bedrock activity on which was built the overall strategic advantage in war of the Western powers.  Operation POINTBLANK - the offensive that took on the Luftwaffe fighter forces from late 1943 - comprehensively defeated the Luftwaffe, gaining a position of air supremacy that was never lost.  This, in turn, put even more emphasis on ground-based defences, that second front, which absorbed such a significant proportion of Germany’s war output in necessarily defending the home population and the means of production. This in Itself is proof of the validity of the targeting in general, while questions quite rightly remain about the specifics of the Bomber Command targeting policy.  Allied attacks on oil and transport effectively seized up movement in Germany, which had becomes even more important after Speer had had to disperse German industry to protect it from the CBO. Overy estimates that through direct and indirect means, the bomber offensive denied 50% of war production that would otherwise have gone to the Eastern and Western fronts.  Control of the skies freed up the airspace of the maritime flank.  And so on…


    Perhaps another way of looking at this is to expand on a quote from Rommel’s senior naval advisor, Admiral Ruge, who commented in 1944 that.. “It was as if the Allies could throw up a new vertical flank on any German position.”  And that regardless of most other aspects of battlefield topography, on the front line and any distance behind it. Such dominance allows for a different way in war, as long, that is, as one has the information superiority to manage it.  Which, given the freedom to roam with reconnaissance sorties, and what we now know about Bletchley Park and ULTRA, the Allies by and large did.


    And here recent academic studies run ahead of the popular histories.  How many readers instinctively know that the Royal Artillery outnumbered the infantry, 18% of the army as opposed to 14% in Normandy?  How many could sketch the incredibly complex command and control arrangements that linked firepower to observers, many in aircraft scouting unhindered across the battlespace, and command nodes linked by tens of thousands of miles of quickly laid and relaid cable? That Quesada’s Ninth Tactical Air Command built 60 airfields in August and September alone (as an aside, how many campaigns in World war 2 have been described as battles for airfields, I’d cite North Africa, the Pacific island-hopping campaign, Italy and Burma).


    The ability to construct such a war machine, relying as it did on our ability to build and move this complicated military society unhindered by consideration of deep enemy fires, against an opposition that had no such advantages, was predicated and reliant on the air dominance that was built on the Combined Bomber Offensive.  I am intrigued by Adam Tooze’s suggestion that if narrative histories did not take as their starting point the front-line experience of the infantry in contact, but instead tried to analyse the war through the management and use of intelligence and joint firepower, a very different history would result.  And it is hard to disagree with David Edgerton when he concludes that behind the myths of Britain alone, and the various tactical heroisms we celebrate, is a ruthless British war strategy that mobilised the resources of empire, and Allies, used machines and firepower rather than expend manpower, and bought victory at surprisingly little cost over six years of war.


    But is this just a statement of the obvious - this is what air forces do? I don’t think so, and we do have other models to compare with.  The Russian Air Forces of World War 2 are not often studied in the West, taking very much a secondary place behind the Red Army. Though that is a tricky distinction given the close coordination and subordination of air to land forces within the Soviet system.  The Soviet air forces became very competent, and could when required provide very effective ground support.  But what it didn’t have was any Independent Force, Stalin sending Tupolev and the team developing a long-range bomber to the gulag in 1937.  So it never targeted Germany, or even German forces, across their depth, and so it never gained the air dominance that became such a factor in the West. Capable of generating local air superiority to support major land battles, it never defeated the Luftwaffe, which remained a force to harry the Red Army in the East throughout, though one increasingly depleted by the demands of the ‘second front’ of the Combined Bomber Offensive that drew off 70% of the fighter force to the West.


    The numbers that result are compelling. British army killed in action over the war numbered 140,000.  Compare that with the Red Army which lost just under 100,000 killed in Berlin in the last three weeks of the war alone.  Of course, that is many ways a simplistic comparison, but it acts as a stark illustration of David Edgerton’s conclusion on costs. It suggests a further justification for venerating the 55,573 bomber command aircrew who were killed, and among those who most benefited are the innumerable Allied soldiers who didn’t lose their lives in a more land-centric strategic approach. (It also forces a re-evaluation of Montgomery - often derided and compared unfavourably with many more manouvrist generals, but whose ‘colossal cracks’ of artillery, and willingness to wait for air power, were greatly valued by his infantry.)


    I closed this section with the thought on Montgomery because it leads to the next section - what do we teach?  For a range of reasons we have come to analyse not the war, and how it was won, but how we could conduct warfare better. Of course we must learn the lessons, but we must be aware of context too, and this can be forgotten if we take single-service, bottom-up, reductive approaches. 


    The dominant period since WW2, which in some ways we remain intellectually, was, of course, the Cold War.  An ideological battle I will not dissect here, the Cold War for military folk was a period of high readiness and certainty.  It became what one might call a high-point in Huntingtonian thinking. The war-fighting could be divorced from the politics.  When the hooter went we all new what we would have to do, and we practised it incessantly.


    Against this backdrop, thinking on how the war-fighting would have to be conducted evolved through the periods of Mutually Assured Destruction and Flexible Response.  The US Army’s experience in Vietnam and its desire to rebuild itself in Spartan terms all contributed to the era of Air-Land battle of the 1980s.  The historiography, interestingly, followed the politics.  And many commentators of this era wrote histories influenced by considerations of the present.  One of the most pervasive and influential memes being that if the Western powers of NATO were going to have any chance of beating a Russian invasion then its armies could not be the citizen Armies of Monty in Normandy, waiting for artillery and air power, but would have to demonstrate the freewheeling elan and ability in the counter-attack of Von Manstein.


    All the foregoing has a Continental, land-centric flavour, and that is true of pretty much all the popular narrative histories, stand fast the more specialised recent research that I have already cited.  This sets a tone, even in professional armed services, and war can come to be seen as the warfare of major land battles stitched together, to which everything else is just so much supporting or preparatory activity. 


    From the 80s on military thinking became dominated by theorising about the operational level of war - which is very seductive for generals of all the services but can too easily divorce considerations of military employment from uncomfortable political realities.  This was the era where each Corps HQ had a CAOC attached, Allied Tactical Publication 35 (that covered Air-land coordination) was the bible, and we could exercise to our hearts content.  Hew Strachan has written extensively on this modus-operandi, and its pitfalls, and I commend his papers of the last decade or so - As Hew put it in Strategy and the Operational Level of War:


    ‘Indeed, that was precisely the attraction of the operational level war, that it was developed in a policy-free zone, in which military expertise was unfettered and where armies reasserted their authority over war’s conduct.’ 


    This chimes with my own experience.


    Certainly the courses that I have been through, and I did the Higher Command and Staff Course in 2006, were definitely pitched at military planning for joint campaigns.  While they discussed strategic matters, the focus and exercise activity was on producing brigade, or at best divisional, commanders.  It was born in 1988 on the back of the rewrite of British Military Doctrine and the need to ensure that a generation who had spent much time in Northern Ireland had not lost its ability to command in what was thought of as proper war-fighting.


    And air forces have happily gone along with this - not least because neither of the sister Services had anything like the Army’s Higher Command and Staff Course, and so piggy-backed on it.  It became joint but retained its original flavour. 


    Further, one has to say that technical services such as Air Forces can get overly focused on the technical side of the job, and so the tactical side of the mission. Hence Mark Clodfelter’s comment in the introduction.  The daily routine of RAFG was very high tempo, and dangerous enough in peacetime - operating fast aeroplanes close to the ground is a full-time, grown-ups game.  And so it is easy to conflate what one does with what one is for.  NATO provided a validation mechanism via the system of annual Tactical Evaluations, and TACEVAL results made or broke careers.


    Go back a few years and you will find that the published doctrine of the Future Air Operating Concept reduced air power and its utility to what it called the Four Key Roles of Air Power.  Control of the air; Attack, Mobility, and Reconnaissance.  And, the demand on air power being what it always will be - look at the Afghan experience - all our fleets have been very busy indeed in these four sectors.  But is that busy-ness a sufficient justification for our business, for what we are and do?  Could it be that there might be other opportunities and, therefore, opportunity costs, in not thinking through more deliberately what air power is for and how it might best solve the fundamental political problem of the war, rather than contribute to the warfare demand of the day?  As General Rob Fry RM once observed, tellingly, “The problem with the Air Force is that is too ready to settle for steady work”.


    Just as illuminating is what we don’t teach, and teaching occurs in many ways not just via our academic courses. Our actions reveal our values.  So I just pose as a question in this anniversary year, how salient has been the 70th anniversary of the Berlin Airlift - and do we see that operation in terms of a strategic defeat for the Soviet Union, or a humanitarian aid mission carried out successfully by aircraft? The 75th anniversary of the Dambusters raid gathered more coverage than the 75th of the victory in the Battle of the Atlantic - a battle that in the terms of war winning achievements that I have sketched was one of the most pivotal. Look for histories of POINTBLANK and you will find almost nothing outside the specialist, academic press.


    I argue that over recent decades Air Forces had become too focused on tactical mission excellence at the expense of thinking at the operational and strategic levels.  I am pleased that that is now changing.  CAS’ recent announcement that he is reforming the famous No11 Group to concentrate on multi-domain command and control will put the emphasis back on working out what to do, not just the management of what we are doing.  We now have a generation of commanders experienced in the most challenging of political and operational environments as they commanded operations against Daesh over Iraq and Syria, and around the Russians. 


    In the Joint arena, as DG Defence Academy, I am pleased to report that we have fundamentally revisited the Higher Command and Staff Course, to introduce the sort of considerations we are discussing today, and it got well reviewed by this year’s cohort. We are reassessing all our courses, and the Royal College of Defence Studies in Belgravia is now host to the National Security Academy where we bring together emerging leaders from all government departments to look at combined, whole of government options for dealing with defence and security problems.  But we still have work to do.


    Before concluding with some thoughts on modern relevance, let me briefly sum-up the foregoing argument: as Churchill said “Air power is the most difficult of military force to measure, or even express in precise terms.”  Used well it can deplete and enemy’s strength such that the surface battles are not necessarily the decisive events in their own right but indicators of the relative balance of power.  Air is one of 3, (or is it five, more in a second) domains in which that battle of relative power is fought out.  Each must be fought comprehensively by environmental experts.   Superiority in the air can swing the balance firmly in your favour if applied correctly and can take the pressure off the other domains.  But the peacetime tendencies all tend to reduce the complexities of war into the relative simplicities of warfare, where air power can come to be seen, reductively, as a supporting activity. Why does this matter?


    It matters because, pace Fukuyama in 1989, history is back. We are now in an era of persistent competition with peer competitors - the most pressing, but not the most important, being a revanchist Russia. A brief look at our competitors shows how much they have achieved without resort to the warfare that we teach and practice. Russia, with a GDP less than Italy’s, has extended its influence from the high-North of the Arctic through the Baltics and Black Sea and into the Eastern Mediterranean. China, with a range of military deployments is slowly dominating the South China Seas, and exerting a presence at other nodes in global trade routes where it had not previously ventured. Iran achieves a staggering level of influence through a relatively small irregular force and its proxy agent in Arabia, Hizbollah. 


    I note three themes in the above threat picture. The first is that the military deployments fall short of our definitions of conflict or combat - they would not trigger a military response from us. The second is that they are a part of a comprehensive effort to enhance and exert national power - Russia has 49 government departments represented in its National Operations Centre on the Moscow River, and we all have now witnessed its skill and capacity in information operations.  China is an acknowledged cyber superpower in qualitative and quantitive terms. The third is that all have looked at our way of warfare - perhaps most vividly demonstrated in 1991’s Gulf War - and have worked out strategies to neutralise it.


    If we look at those strategies they have an ethereal quality to them - and I use ether here in the sense that Nikola Tesla would have understood it.  Our technological advantage has been gradually eroded in the last two decades.  In the fields of cyber, space, air-defence, ballistic missiles, electronic warfare, hypersonics - the threat is coming at us through the ether.  And it should be seen as a threat rather than a latent warfighting capacity, though it is that too.  The phrase A2AD - standing for Anti-Access, Area Denial - has become au courant in recent years.  It is a recognition that our competitors’ deployments have been aimed at frustrating our decision-making, making certain regions no-go areas in our own minds.  This is reinforced by threatening a range of strategic punishment responses aimed to deter us from action - The Russian doctrine of SODCIT does precisely that - and here the cyber threat has become the most salient.  The recent revelation of threats to undersea cables being but one manifestation.


    How we respond to all this is moot.  And in a link with the earlier part of this lecture I quote Rommel on the eve of D-Day, when he cautioned his staff not to expect the Allies to bring their own version of the Blitzkrieg that he himself had waged so successfully in France in 1940. This was going to be something new…


    So I certainly do not advocate recreating Cold War structures - rebuilding RAF Germany and the British Army on the Rhine would bankrupt us in preparing for the war that is unlikely to come.  But we must rebalance the uncertainty in political decision-making, we cannot allow the A2AD mindset to propagate, and must generate at least as much doubt in our competitors minds over the reliability of their own systems if threatened in return.  We now consider there to be five war-fighting domains when you include space and cyber. The lesson from the history of the RAF as an independent service is that you have to fight comprehensively across all the domains, you cannot prioritise one and hope to cherry-pick benefits from the others, except at some cost.  And you must keep re-imagining ways in war.


    There are obvious things we should do and are doing: we should build resilience into our space and cyber networks, we should demonstrate the ability to respond rapidly, and do so throughout the ‘ether’, and so on… We need to be able, to use Admiral Ruge’s phrase in a new context, to throw up a vertical front in all these ethereal domains, one that frustrates the opposition and denies it freedom to manoeuvre, as air power did to Rommel.   In short we need counter-strategies - and we need to think beyond geographic boundaries. And I accept that ‘strategy’ is an over-used and contested word


    Lawrence Freedman in his opus Strategy: A History, offers a simple definition of strategy: it is what you use to maximise latent power.  And throughout his book he demonstrates that one of the best ways to maximise that latent power is to co-opt the power of friends and allies.  I hope in this lecture I have shown that the independent Royal Air Force has almost always acted in partnership, the Combined Bomber Offensive being a prime example.  And that continues today in the air, space and cyber environments. Even routine training missions over the North Sea regularly have an international dimension. When the USAF created the Information Warfare Centre in 1995 RAF Air Warfare Centre personnel were seconded to it. Many of them are still leading lights today in the UK’s cyber enterprise. We burden share over Electronic Warfare development and in all manner of Intelligence Surveillance and Reconnaissance missions. We work, and demonstrate combined resolve, with regional partners through NATO and also the 9-nation Joint Expeditionary Force, whose air element will be working together to realise synergistic benefits as we grow the P8 and F35 forces with Norwegian, Italian, Dutch, Danish and American partners, and of course Australia in the Asia-Pacific.


    And that brings me full circle to Trenchard.  A lesser known element of his Independent Force is that a few weeks before the 1st World War ended it was renamed as the Inter-Allied Independent Air Force, and took squadrons from the French, Italian and American air services under command.  It is a useful final note demonstrating the enduring power of Trenchard’s vision.  It is fitting to end on that conclusion in this centenary year. I thank you for your patience and will happily take questions. 


Explore our related content