'Thunderclap' (ii) was an Allied unrealised plan to end the war against Germany by the use of bombing to bring about the destruction of Berlin (August 1944/April 1945).

In its original form the undertaking envisaged a massive air attack on Berlin to cause an estimated 220,000 casualties including 110,000 killed, many of them key German personnel, in an effort which, it was believed, would shatter German morale. It was then decided, after further consideration, that the concept was unlikely to work and it was therefore abandoned.

The concept was considered once again at a time early in 1945 for implementation in co-ordination with a Soviet advance, but was again rejected as impractical. A number of smaller but closely co-ordinated attacks was instead planned against German cities in the communications zone behind the Eastern Front, through which key routes to the east converged.

The cities designated as chokepoints, where bombing would, it was believed, achieve maximum results for the land campaign were Berlin, Chemnitz, Dresden and Leipzig. Intensive bombing of these targets was carried out with the intention of disrupting the rear areas of the German forces on the Eastern Front, and so aid the Soviet advance, as had been requested by the Soviets at the 'Argonaut' conference at Yalta. These raids were large, but not undertaken on a scale as massive as those envisaged in the original 'Thunderclap' (ii) plan. Some preliminary raids were undertaken (one of these leading to the virtually total destruction of Dresden on 13 February 1945), but the speed of the final Soviet advance made unnecessary the full implementation of the scheme, which was not liked by air planners as it was designed not just to end the war but to convince the Germans that any organised resistance after the formal end of hostilities would be futile, and merely bring about massive retribution; it was also intended as a warning to the Soviets of Allied strategic air power.

The raid on the historic city of Dresden was perhaps the most controversial single event in the Allies' strategic air offensive against Germany. Capital of Saxony and located on the Elbe river, Dresden was particularly noted for its splendid architecture and its manufacture of fine china. It had little heavy industry, and by a time early in 1945 had been attacked just once from the air, when the US 8^th AAF delivered a small raid during October 1944.

It was during January 1945 that the British air ministry drew up its 'Thunderclap' (ii) plan for attacks on Berlin and the population centres of eastern Germany. This concept was designed to take advantage of the recently launched Soviet offensive westward from the Vistula river, and to add to the growing chaos in Germany by disrupting the flow of refugees seeking to escape the Soviet onslaught. At the same time, the Western Allies wished to demonstrate to the Soviets at the forthcoming 'Argonaut' conference at Yalta that they were providing the support of their heavy bombers: at Yalta the Soviets specifically requested help in this form.

In the meantime, Lieutenant General Carl A. Spaatz and Air Chief Marshal Sir Arthur Harris, commanding the US and British strategic bomber forces, had been instructed to implement elements of 'Thunderclap' (ii), and the scheme was first undertaken in the form of US daylight attacks on Berlin and Magdeburg on 3 February, Chemnitz and Magdeburg on 6 February, and Magdeburg again on 9 February. It was the intention of Harris to strike Dresden first, but weather conditions were initially unfavourable. On 13 February the weather showed a measure of improvement, although it were still not adequate for the original plan of an initial US attack during the day.

On the night of 13/14 February, however, RAF Bomber Command despatched 796 Avro Lancaster and nine de Havilland Mosquito bombers from English bases. These attacked Dresden in two waves spaced three hours apart, dropping 1,478 tons of HE bombs and 1,182 tons of incendiaries. The first wave of the attack was undertaken solely by aircraft of No. 5 Group, using the group’s own low-level marking methods. A band of cloud still remained in the area and this raid, in which 244 Lancaster aircraft dropped more than 800 tons of bombs, was deemed to be only moderately successful. The second wave was delivered by Lancaster bombers of Nos 1, 3, 6 and 8 Groups, with No. 8 Group’s aircraft providing standard Pathfinder marking of the targets. The weather was now clear, and the 529 Lancaster bombers dropped more than 1,800 tons of bombs with great accuracy. A firestorm, similar to that which burned out the heart of Hamburg in 'Gomorrah' during July 1943, was created and large areas of the city were burned out.

It has never been possible to discover how many people died, but it is generally accepted that the number was greater than the 40,000 who perished in the Hamburg firestorm, and the Dresden figure may have exceeded 50,000. So weak were the German defences that Bomber Command’s casualties were just six Lancaster bombers shot down, with another two crashing in France and one more in England as the force returned home.

On the following day, 311 Boeing B-17 Flying Fortress bombers of the US 8^th AAF dropped 771 tons of bombs on Dresden, with the railway marshalling yards as their aiming point. Part of the North American P-51 Mustang fighter escort was ordered to strafe traffic on the roads around Dresden to increase the chaos. The Americans bombed Dresden again on 15 February and once more on 2 March, but it is generally accepted that it was the RAF’s night raid of 13/14 February which caused the most serious damage.

Controversy about the morality of destroying a city of negligible military significance and full of hapless refugees started very soon after the Anglo-American raids, and had continued with little abatement ever since.