By Stephanie Linning for MailOnline Historian Monika Siedentopf believes that Nazi spy chief Herbert Wichmann, pictured, wanted the German invasion to fail Germany sent 12 Nazi spies to Britain in September 1940 to gather information ahead of Hitler's planned invasion. But most of the agents who arrived as part of Operation Lena were arrested without having come close to completing their mission 'because of their own stupidity', according to official records. One was arrested when he tried to order cider at 10am - not knowing that he could not be served before lunchtime during the war - while another two were spotted cycling on the wrong side of the road.
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Germany sent 12 Nazi spies to Britain as part of Operation Lena in 1940
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Many of them were caught 'because of their own stupidity'
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Historian believes they were sent to sabotage Germany's plans to invade
The reason why @placeholder, known for meticulously-prepared spies, sent such incompetent agents on one of the most important missions of the second world war has remained a mystery