Johann-Nielsen Jebsen, nicknamed "Johnny", was an anti-Nazi German intelligence officer and British double agent (code name ARTIST) during World War II. Jebsen recruited Dušan Popov (who became the British agent Tricycle) to the Abwehr and through him later joined the Allied cause. Kidnapped from Lisbon by the Germans shortly before the Normandy landings, Jebsen was tortured in prison and spent time in a concentration camp before disappearing; he was presumed killed at the end of the war. In a 2012 reassessment of the Allies' use of double agents in World War II, historian Ben Macintyre called Jebsen a hero. Jebsen features extensively in Popov's book Spy-Counterspy. Jebsen was born in Hamburg in 1917, heir to the shipping firm Jebsen & Jebsen. His parents, who both died while Jebsen was still a child, were of Danish origin, but held German citizenship after they had moved the company to the country. Early in his life, Jebsen considered his citizenship a convenience, with deep roots remaining in his Danish ancestry. During childhood, he visited England and became enamoured with the country, adopting the mannerisms and the language. Jebsen attended the University of Freiburg during the 1930s, where he became close friends with Duško Popov. During this time, both showed distaste for the Nazi regime that was emerging in Germany. After graduation, Jebsen moved to England, intending to study at Oxford University, although it appears he never did this. Over the next few years he moved amongst the London social set, befriending P. G. Wodehouse amongst others. At the outset of World War II, Jebsen joined the German military intelligence agency, the Abwehr, largely to avoid compulsory service in the army. He was given a vague brief as an independent "researcher" and assigned the rank of private. In reality, it meant he could continue his normal activities as an international businessman, so long as he was available to help the Abwehr when it required.