A typical Lancaster bomb load during the Berlin attacks comprised high-explosive bombs, including a 4,000lb `cookie' and incendiaries.
Nicknamed the `Big City' by the crews of Bomber Command, the German capital was one of the most feared of targets. Berlin was a formidable prospect: it meant the heaviest of defences and a long flight over enemy-occupied territory.
Almost 600 miles from London, early in the war Berlin was close to the maximum range of the then available bomber aircraft types. Nonetheless, the first RAF raid was mounted at the height of the Battle of Britain on the night of August 25, 1940, when 95 aircraft were dispatched. Five more `ops' were flown over the next two weeks and others followed over the next year. But difficulties in navigating accurately led to the small loads dropped being widely dispersed and after November 1941 Berlin was not attacked again until January 16/17, 1943.
The arrival of Air Chief Marshal Sir Arthur Harris as C-in-C in 1942 reinvigorated Bomber Command as it steadily increased in size and effectiveness. New tactics evolved, such as the `bomber stream', and new navigation and targeting aids meant that by early 1943 Harris was ready for what he described as his main offensive.
This campaign was to last a year and feature a series of `battles'; the concept being to repeatedly concentrate the `Main Force' against a particular objective until it was deemed to have been destroyed. The principal, and most effective, weapon for the campaign was the superb Avro Lancaster.
Throughout the spring of 1943, the industrial heartland of the Ruhr valley was the target for the first of the epic set-piece, followed by a brief assault on Hamburg that destroyed much of the port city.
From the outset it was established that for cogent tactical reasons, as well as those imposed by the weather, none of these battles would exclusively focus on the capital. A resolute campaign against Berlin would have allowed the enemy to concentrate defences, so route variations, tactical feints and new devices were introduced to outwit the Germans.
But the defenders were very adaptable. The RAF's introduction of `Window', which disrupted radar pictures, led to the development of new and highly effective tactics: single-engined Wilde Sau (Wild Boar) fighters flew over the target to acquire bombers visually - followed later by long-range radar-equipped Sahne Sau (Tame Boar) nightfighters. Both were to reap a grim harvest through the coming winter. Before the campaign began there were several precursory attacks in the late summer of 1943. The first was on the night of August 23/24 when 710 bombers were launched on the heaviest Berlin raid to date.
On the night of November 18/19, Harris opened the Battle of Berlin proper, with the first of a series of 16 attacks. So as to disguise the primary purpose, smaller raids on other targets were mounted to split the enemy defences, often flown by the more vulnerable Stirlings and Merlin-engined Halifaxes.
As expected, Berlin's highly co-ordinated defences inflicted heavy losses on the bombers. To keep the Germans guessing, at times dummy raids were staged on Berlin when other cities were the main target. Leipzig was twice the centre of Bomber Command's attention, requiring very long transits and exposing the Lancasters to unremitting high risk.
Approach and egress routes to the `Big City' became more complex as the campaign evolved. Streaming via Denmark, with lots of course changes en route to the target was adopted as a tactic. Longer legs via the Baltic, providing a route to Berlin from the north, also added an element of surprise. The flight path home was also changed on a sortie-to-sortie basis.
The Battle of Berlin witnessed the advent of Schrage Musik, deadly upward-firing cannon mounted in the upper fuselage of night-fighters. This enabled the defending fighter force to approach bombers from below, with fires on the ground and searchlights illuminating their quarry. On the bombers, front and rear gunners scanning the skies for fighters would have their vision blurred by looking down on the light sources.
The final raid of the Battle of Berlin came on March 30/31, a `maximum effort' against Nuremberg, a diversionary strike to keep the Luftwaffe guessing. A total of 96 aircraft fell, Bomber Command's worst night of the war. Despite immense courage and unimaginable hardship and sacrifice by the men of Bomber Command, the assault on the `Big City' ended in operational failure that some historians have described as being not just a defeat, but a disaster.