However, the fact that there was an intense assault on merchant shipping going on during 1940 comes as something as a surprise to many casual observers, stemming in part from the fact that, in many popular histories, events labelled as the Battle of the Atlantic often start in the Spring of 1941. Earlier fighting is often called "skirmishing" or "preliminaries".

In some narratives, the battle starts in March 1941 with a directive from Winston Churchill writing in his role of minister of defence. In others, it is dates from 4 April 1941, when shipping minister Ronald Cross announced that Churchill had "personally taken charge".

Another possible starting point could be Adolf Hitler's speech in Berlin on 30 January 1941. Then, he made rather an odd statement, telling his audience that submarine warfare would "begin" in the spring. "They will notice that we have not been sleeping! And the Luftwaffe will also properly introduce itself to them! Our whole Wehrmacht will force a decision, one way or another!", he declared.

And what he openly advertised in Berlin, he formalised on 6 February 1941 with Führer Directive No. 23 - which could also be taken to mark the start of the true Battle of the Atlantic. 

Whatever the actual starting point - or the name, for that matter (to which we will return) - this was a most interesting directive. In its preamble, Hitler more or less acknowledged that trying to break the morale of the British people by bombing their cities was an uncertain endeavour. But he was also conscious that the German air campaign against Britain could not be sustained once units had been redeployed to "other theatres of war" – i.e., to the Eastern front for Operation Babarossa.

But what put the broader battle into focus was Hitler noting that "in contrast to our earlier conceptions", the greatest success in the struggle against the English war economy had been "the heavy loss of merchant ships through naval and aerial warfare". Here, he is recognising that, of the diverse measures taken against Britain, the attack on shipping had been the most successful.

To confuse the issue, Hitler also noted that the effect of the direct attacks on shipping, by sea and air, had been further reinforced by the destruction of port installations and of large stocks of material, as well as by the lessened utilisation of the ships when required to sail in convoy. 

Thus, whatever Churchill or others may have decided to call it the battle, Hitler actually launched a multi-faceted assault on the "English war economy", which started in September 1939. This had been set fully in train with Führer Directive No. 9 of 29 November 1939, amended on 26 May 1940, and then reinforced by Directive No. 17 of 1 August 1940, the directive that declared unrestricted submarine warfare.

One of the problems with nomenclature comes, as far as I can see, with the characterisation of the entire battle as a U-boat war, associating the Atlantic War exclusively with just that one part of the battle.

In reality, in the early period, the assault was by no means, or even primarily, a U-Boat war. German went to war with only 26 ocean-going boats and until the Spring of 1941, rarely deployed more than 20 at any one time, the graph rising from the end of April 1941 to March 1943 when a peak of 160 boats was deployed.

Thus, the early campaign comprised actions by surface raiders (some disguised) throughout the world. It included attacks by long-range aircraft – mainly FW 200 Condors (type pictured above), which from August 1940 were based in France. 

The campaign also took in the attacks by short and medium range aircraft on coastal shipping, and the bombing of ports (including London), together with attacks on railways and communications. It also embraced an extensive minelaying programme, by air and sea, and attacks on shipping by the torpedo and gun-equipped fleet of so-called E-boats. And much of this activity was in the North Sea, the Channel and the Irish Sea, and their related coastal areas, rather than the Atlantic.

Even with his directive of 6 February 1941, Hitler was setting out a template for a combined arms assault - not just U-Boats but naval and air forces. With the addition of concentrated air attacks, he wrote, "primarily against targets which coincide with those of naval warfare", he could confidently expect "the collapse of English resistance within a reasonable time".

Until the beginning of deployment for Barbarossa (which was to start on 22 June), the Führer thus decided that these forces "should strive to step up aerial and naval operations progressively, not only to inflict the greatest possible damage to England, but also to simulate the appearance of an impending attack on the British Isles".

And the Luftwaffe certainly played its part. In Match 1941, it flew about 4,400 night sorties over Britain, rising to 5,500 in April and dropping back only slightly to 4,500 in May.

During that period, major attacks were launched on Merseyside, Clydeside, Belfast, Cardiff, Plymouth, Bristol, Southampton and Portsmouth – as well as London, the largest port in the Empire, plus Hull, Newcastle and multiple northeast towns.


On the worst night of the attack on Liverpool, 3 May 1941, SS Malakand, loaded with a thousand tons of munitions, caught fire, blew up and obliterated the Huskisson Dock. It is thought that a drifting barrage balloon landed on the deck and burst into flames. Pieces of the ship were blasted over two miles away causing damage to the Overhead Railway.

Half the docks were temporarily put out of action as a result of the destruction caused by the blast. Thousands of dock workers, troops and volunteers were involved in the clear-up. Miraculously, considering the size of the blast, only four people were killed. But so intense were the raids as a whole that Churchill was to suggest that, had the Luftwaffe persisted with them, the Battle of the Atlantic would have been much more closely run than it was.

Now, if we step outside the normal framework and define battles (and campaigns) not by the methodology of their execution, and/or the instruments used to effect them – or their targets (actual or intended) - but by the over-arching objectives, it becomes clear that this bombing was part of the "blockade" or the "assault on the English war economy".

Furthermore, we know the invasion plan and the struggle for local daylight air superiority that went with it, and the attempt to destroy the morale of the public in order to achieve regime change, were all part of the same campaign. And this is the one we know as the Battle of Britain.

Thus are we back to the thesis of this series. The Battle of Britain, rather than a limited daylight air war between RAF Fighter Command and the Luftwaffe, was a continuous period largely defined by the fall of France until he invasion of Russia, involving the three phases or pillars that we have defined. That includes some part of the conflict known as the Battle of the Atlantic, however it is defined.

The significance of this is, of course, profound. It restructures an important part of the Second World War and, thereby, changes our understanding of it. 

Looking at the situation as is, in popular terms, the early part of the war is often seen in phases. The first is the period from the start of the war until May 1940. We then have the Battle of France, the Battle of Britain, and the Blitz (with some overlap). This is followed by the Battle of the Atlantic.

If one now redefines the structure, guided in part by Hitler's objectives, there is a merging of the parts. The segment which is called the Battle of Britain merges with the Blitz, both of which merge with the assault on the "English war economy". They became a single, if multiphasic, battle.

For convenience, we could call this the Battle for Britain, as indeed it was sometimes called at the time. It is then entirely rational to argue that the U-Boat war in the Atlantic, running from the Spring of 1941, to the end of the war, was a phase of the Battle for Britain. For those who wish to make the distinction, it can be labelled the "U-Boat war", or even retain its label "Battle of the Atlantic", as a sub-division of the Battle for Britain.

And now we get to the really interesting bit. Throughout the telling of the history of the Second World War, there seems to be a huge amount of confusion as to the nature and structure of this part of the war, its labels and terminology.

As always, one can see the attractiveness of dividing the war into neat divisions, with simple labels, but over-simplification or false divisions do not make for clarity or understanding. Yet, seventy years on, confusion seems to remain. How it came about, and why, we'll look at in Part V, the final part of this series.