'Tiegel' was the German bombing campaign against the British city of Sheffield (12/16 December 1940).

At this time Sheffield had a population of more than 550,000 persons, and was characterised by its many heavy industries, centred around steel and armaments, including the only facilities for making the crankshafts for Rolls-Royce Merlin engines and 18-in (457-mm) naval shells. In 1945, the capture of German documents revealed that the Luftwaffe.s targets had included the Atlas Steelworks, Brown Bayley Steelworks, Meadowhall Iron Works, River Don Works, Darnall Wagon Works, Tinsley Park Collieries, East Hecla Works and Orgreave Coke Ovens.

During the afternoon of 12 December, British monitoring stations detected that X-Gerät radio navigation beams were being laid across central England, and calculated that the probable target of the coming raid was Sheffield. The raid was delivered by three main groups of aircraft flying from airfields in the northern part of German-occupied France. Some 13 Heinkel He 111 aircraft of the Kampfgruppe 100, the German air force’s specialist pathfinder wing, overflow the city at 19.41 and dropped 16 110-lb (50-kg) HE bombs, 1,009 medium incendiaries and 10,080 light incendiaries. The leading element of the main attack force comprised three waves of 36 Junkers Ju 88 and 29 Heinkel He 111 bombers. The second element comprised 23 Ju 88, 74 He 111 and seven Dornier Do 17 bombers. The last group comprised 63 Ju 88 and 35 He 111 bombers, a total of 280 aircraft.

At about 21.30 a stick of bombs fell on Campo Lane and Vicar Lane, demolishing the western end of Sheffield’s cathedral. At about 12.50 a 1,102-lb (500-kg) bomb fell on and destroyed the C&A building opposite the Marples Hotel in Fitzalan Square. At 23.44 the Marples Hotel itself received a direct hit. It is not known exactly how many people were killed but some 70 bodies were recovered from the rubble. This was the greatest single loss of life in the attacks. During this stage of the attack most bombs fell on the centre of the city and also on residential districts, the last bombs falling at 04.00. In all, the Germans had committed 336 aircraft, which had dropped 355 tons of HE bombs and 457 canisters of incendiaries.

The second night of the campaign against took place on 15/16 December, and was marked by the first use of a new German pathfinder tactic: the aircraft no longer carried HE bombs, but only increased load of incendiaries. On this night the pathfinder force was 16 He 111 machines, and these dropped 11,520 incendiaries between 19.00 and 19.50. The main raid involved 50 He 111 and 11 Dornier 17 bombers, and ended at 22.15. Many steelworks, including Hadfields, Brown Bayleys and Steel, Peech and Tozer, were hit, but the damage was not serious enough to affect anything but short-term production. In all, the Germans had committed 94 aircraft, which had dropped 80 tons of HE bombs and 600 canisters of incendiaries.

In the two raids more than 660 persons were killed, 1,500 injured and 40,000 rendered homeless. Some 3,000 homes were demolished, 3,000 badly damaged, and another 78,000 homes less damaged.