In 1940 Sheffield was a city of about 560,000 people and contained many heavy industries, primarily centred around steel and armaments. The Vickers works was host at the time to the only drop hammer in the country capable of forging crankshafts for the Rolls Royce Merlin engine which powered the Supermarine Spitfire fighter plane and later in the war the Avro Lancaster bomber. Hadfields steelworks was also the only place in the UK at that time where 18 inch armour piercing shells were made. Most of the factories were located in the East end of the city beside the River Don.
The full moon was on the 14th of December 1940 and both blitz nights were cold and clear.
The attacks were made by about 300 aircraft of the Dritte Luftlotte, mainly Junkers Ju 88s, Dornier 17s and Heinkel 111s flying from airfields in German-occupied France. The German code name for the operation was Crucible.
On the night of the 12th of December, the first bombs fell about 7pm and the last bomb fell about 4am.
The intention of the raid was to destroy the factories in the East End however the first wave of planes, mainly incendiary carrying Heinkel 111s, marked the centre of the city and by 9pm many fires were blazing. At about 9.30pm a stick of bombs fell on Campo Lane and Vicar Lane demolishing the west end of the cathedral. At about 10.50pm a 500kg bomb fell on and destroyed the C&A building opposite the Marples Hotel.
Just before midnight, The Marples Hotel in Fitzalan Square received a direct hit. It is not known exactly how many people were killed but approximately 70 bodies were recovered from the rubble. This was the single biggest loss of life in the attacks.
In total over 660 lives were lost, 1500 more were injured and 40,000 were made homeless. 3,000 homes were demolished with a further 3,000 badly damaged. A total of 78,000 homes received damage.
King George VI and Queen Elizabeth toured the city soon after the devastating raids to inspect the damage and boost morale amongst survivors. Prime Minister Winston Churchill also toured the blitzed city speaking to a 20,000 strong crowd in Town Hall square through loudpeakers giving his signature V hand sign for Victory.