In 1936 the Spanish Civil War flared into life and the leadership of the Nationalist forces asked the governments of both Italy and Germany for military support. Although Germany itself could not afford to take a formal part in the war, units of volunteers were made available in support of the Nationalists. Among them was a Panzer unit, given the code-name Abteilung Drohne, which was officially named Panzer Abteilung 88. It was commanded by Major Ritter von Thoma and it was drawn from the ranks of the 4th and 6th Panzer regiments. Although the men really were volunteers there was no shortage, and there were sufficient men to form a company and a workshop column. The volunteers were transferred on German passenger ships as civilian members of the trade union travel organisation, which worked under the slogan ‘Strength Through Joy’. They took with them Panzer I tanks and were disembarked at Seville. The training role was a real one, and the German troops were responsible for training Spanish National troops equipped with captured T-26 Russian tanks. The volunteers themselves first saw action in October 1936 when a few Panzer I tanks were deployed to support the Nationalists in their drive on Madrid. In early 1937 the unit was reinforced to form three combat companies and a support column. The German tanks were used in numbers for the first time on 11 May 1937 when they took part in a concerted attack on the Spanish Communist positions near Eremita. The volunteers remained in Spain for over two years and were returned to Germany only in February 1939. In his first report of the action in Spain sent back to Germany in December 1936 von Thoma was quick to point out the limitations of the Panzer I. He noted that from the very outset a gun armed tank was far superior to the machine gun armed Panzer I, although the disadvantage could be overcome to an extent by issuing specially hardened ammunition which could cleanly penetrate Russian tanks at ranges of about I20-150 metres.
The Russian tanks, however, quickly adapted their tactics and were able to stay out of range, moving to over a thousand metres away where their superior guns made the Panzer 1 easy prey. The German tanks were particularly vulnerable if the Panzers remained stationary, and von Thoma’s orders were to fight constantly on the move. Despite these precautions at least seven Panzers were knocked out by the Russian forces in a single engagement.
The solution to the limitations of the Panzer I in Spain was to attach anti-tank guns to each of the Panzer companies. Once again, with the result of practical experience in the field, von Thoma came to the conclusion that the Panzer I, if it was to be used at all, needed to be accompanied by an infantry support tank which had at least a 7.5cm gun with a range of up to three thousand metres. It was also felt that a better anti-tank gun was needed, with a range of at least 1,500 and not the 900 metres; once again the 37mm gun which was deemed to be inadequate for the task.
Of course the Germans were not the only foreign nationals present in Spain. Both Britain and France had their observers to view the progress of the war. General Fuller wrote an article in the Times on 8 April 1937 which was highly critical of the tanks that were seen in action, particularly the German machines, which Fuller described as ‘mobile coffins’. The French went even further and in April 1937 a French newspaper article was particularly critical of the German tanks. It noted that they were a major disappointment because of their slow speed across country and the armour, which was accurately described as almost useless. There was little real defence against enemy anti-tank guns; from a close range even rifle bullets could penetrate them. The French report concluded that although the French tanks were slower they were much better protected and remained ‘king of the battle ground’. Altogether approximately one hundred and fifty one Panzer Is were sent to Spain and all were left behind at the close of hostilities.
A group of seven Panzer Is serving with Gruppe Thoma in the Spanish campaign during 1937. The many limitations of the Panzer I were clearly demonstrated in the Spanish Civil War, but the lack of a viable alternative meant these machines would see considerable service during the early years of the war.
In the official Report of the Spanish Civil War which was written in March 1939, it was noted that the light tanks were useful only with flamethrowers since it was impossible to fire the machines guns on the move. Once again it was forcefully noted that the Panzer I was an inferior tank. However, during the time of the Spanish Civil War the expansion of the Panzer forces back in Germany continued relatively smoothly, as did the production of the vehicles.
The harsh evidence from the battlefields of Spain did not go unheeded.
As soon as the Panzer II became available from October 1936, resources were immediately switched and there was no effective increase in Panzer I strength, which remained about 1,400 machines until the outbreak of the war. The number of Panzer IIs rose rapidly from 115 in May 1937 to 1,200 in September 1939. Additionally the first of the Panzer Ills came on stream in October 1937 to be followed by the Panzer IV in January 1938. By the outbreak of the Second World War in September 1939 there were 98 Panzer III in service and 211 Panzer IV, the most useful machines therefore still counting for a tiny proportion of the forces available.