This week's Holocaust Educational Trust dinner prompted thoughts about what could have been done by Allied powers to reduce Jewish deaths in the Shoah. But the issue is wider still: could Britain have saved all Jewish lives by better preparing its armed forces to the extent that the Second World War might have been averted? Could better preparation have saved not just the millions of lives lost in battle and civilian casualties — and specifically the Holocaust, by preventing Hitler’s territorial gains?

This is one of the most fundamental questions that can be asked of the period. According to one argument, if a capability had been retained after 1918 that could take on a sophisticated peer adversary in Europe, and if Britain’s government had retained a willingness to preserve the peace using the type of military deterrence exercised against the USSR via NATO, the War might never have happened.

Hitler and his Wehrmacht were nervous about possible British and French reactions to the illegal reoccupation of the Rhineland in March 1936. In the event France and Britain did nothing, directly encouraging Hitler’s ambitions elsewhere.

In part, this was because Britain did not have at its disposal in 1938 or 1939 an army able to intervene militarily on the continent against the Wehrmacht. The British government could not threaten the Germans with something it did not possess.

The British Army was catastrophically unprepared for war in 1939. But it wasn’t just the army that was unprepared. Despite a last-minute rush to re-arm (which primarily benefitted the RAF), so too was the whole country. A deep-seated passivity had set in following the end of the Great War. This belied the reality that in Europe the ending of the war opened the door to unheralded political chaos and instability that was in time to overcome the forces of stability and would lead directly to yet another devastating war.

In the years immediately after 1918 Britain hoped it could close the door on any future European commitment and return to the halcyon days when its only security commitments were the defence of its widely flung Empire.

The weakness at the heart of British planning for war was a direct reflection of Britain’s strategic, political, societal and economic situation during the inter-war period. Britain simply wasn’t mentally prepared to go to war again so soon after the trauma of the Great War. As a result, it made no proper preparation for another full-on industrial war against a peer opponent on the continent. This was fundamentally a failure of political and military imagination .

In our book, Victory to Defeat, we have identified five primary causes of the decline of British military effectiveness in 1939. First there was no clear strategic plan for the army. Following the end of the Great War, no one seemed bothered to define this essential point of direction. There was plenty of talking, but very little focused on a realistic determination as to who it might have to fight, and how. Was the focus of the army to be the continent or the Empire, or both? No one knew. As a result, the last known plan reasserted itself — Imperial defence, à la 1914. This meant that the army wasn’t structured or equipped to fight a specified enemy in a defined set of circumstances. Instead, the British Army and its cousin, the Indian Army, was expected to be a generic jack-of-all-trades, without the structure, doctrine, training, or equipment to fight the type of war it had become the master of in 1918.

There was no operational design for the British Army derived directly from an analysis of the threat it faced. If there had been, then the British Expeditionary Force would have been prepared for the German Blitzkrieg in France and the Low Countries in 1940. But the British Army wasn’t prepared to fight a first-class European Army in 1939 for the simple reason that Britain hadn’t prepared itself to do so.

Second, as a country, Britain was unprepared both politically and culturally for another war so soon after the last. In 1919 the country seemed to want to look backward to embrace the days of peace that had preceded the cataclysm of war. It was tired and disillusioned, and felt no victor’s triumph. Part of this sentiment evidenced itself in the rise of pacifism. In the army, a pervasive belief existed that the Great War was an aberration, and nothing like it would again afflict western civilisation. Any lessons from the war were therefore irrelevant to the future structures or doctrine of the British Army, for whom the defence of the Empire was the crucial issue.

But whether it liked it or not, the world was changing fast, in ways that Britain struggled to comprehend and from which it could not escape. The Russian Revolution, the rise of fascist dictators in Europe, isolationism in the USA (except for a new American assertiveness in Asia) and the increasing militancy of Japan began changing the global landscape in ways that were hard to understand for a country once in total charge of the certainties of statecraft. Now it struggled to find its way in a new world of tension, turmoil and rapid change.

Third, no one in the British Army thought to capture the reasons for operational success in 1918. The dramatic reduction in troop numbers at the end of the Great War meant that those best able to convert the lessons from 1918 left for civilian life, taking their knowledge and experience with them.

Fourth, political naivety led to a dramatic economic stringency. This meant there wasn’t enough money to do what was necessary to protect British interests. The Army butter was thinly spread on the imperial bread, with the result that insufficient investment was made in the core of the army’s warfighting capability. This was exacerbated by the impact of the Great Depression.

These factors coalesced with a new global instability caused by the rise of a new breed of irrational actor in Germany, Italy and Japan which overturned previously held notions of diplomacy and state behaviour. Britain was unprepared for this political discombobulation, with a form of European politics never seen before, driven by racist ideology rather than rational statecraft. Who could have foreseen the rise of irrational national actors, prepared to lead their people into a populist (and racist) doom? No published strategic assessments during this period understood this frightening development and had not prepared for the military manifestation of such ideas.

This vacuum allowed competing visions for technology, doctrine and equipment to be endlessly debated, and for there to be no effective plan for the realistic equipping and training of the army. The army allowed itself to become intellectually moribund, boring and regimental, and a home for the uninquisitive. As a consequence, the quality of military leadership was poor.

Arguably, it was only in 1944 in North-West Europe and in India and Burma that the lessons hard won in 1918 were hard won again.

The stark message of the two decades between the world wars is that we neglect to understand who our enemy might be, and how to defeat him, at the peril of our country.

General Lord Dannatt is a former Chief of the General Staff and Dr Robert Lyman is a military historian.
Victory to Defeat: The British Army 1918-40 is published by Bloomsbury