'Nickel' was the British overall designation of air raids against Germany in which offensive armament was replaced by loads of leaflets urging the German civil population to abandon the war (1939/40).
Such raids were made by Air Marshal Sir Richard Peirse’s RAF Bomber Command at the express demand of the British government, which feared that the dropping of bombs on German soil would inevitably bring about retribution by German bomber forces, themselves wrongly believed to be considerably more powerful that those of RAF Bomber Command. The British aircrews had to endure all the operational disadvantages of offensive warfare, together with the dire winter conditions of the period, yet could achieve little of strategic importance, and learned little about the need for total accuracy of nocturnal air navigation.
The first such raid was flown on 3/4 September by Armstrong Whitworth Whitley aircraft of Nos 51 and 58 Squadrons, which dropped 5.4 million leaflets over targets including Hamburg, Bremen and the Ruhr. By 27 September RAF squadrons had dropped 18 million leaflets over Germany. On 12/13 January 1940 Whitley aircraft of No. 77 Squadron, operating from Villeneuve in France, dropped leaflets over Prague and Vienna for the first time.