Notable spy cases

The Security Service was established in 1909 (in its first incarnation as the Secret Service Bureau) in response to fears of German espionage. Over the next eighty years, MI5 identified numerous spies from Germany, the Soviet Union and other countries during the two World Wars and the Cold War. Foreign spies typically sought to obtain political and military intelligence, and during the wars some sought to carry out acts of sabotage. Many of our files on these cases have been released to the National Archives, the organisation responsible for storing and protecting the UK government's historical files, and can be viewed by the general public.

The people involved in these cases included men and women, young and old, from dozens of countries. Their stories were as varied as their identities. Some acted out of patriotism, while others were motivated by ideology or were forced into acting as spies. Others simply wanted money or adventure.

Three particular cases show how three spies operated in the three great conflicts of the 20th century: the First World War, the Second World War and the Cold War. Each of the spies had different motives - patriotism, adventure or ideology - and each had different fates. Click on the links below to learn more about them and read original MI5 documents on their cases.

• Carl Hans Lody was a German naval officer and spy in the First World War. He travelled to Scotland and Ireland to spy on the Royal Navy and British defences. However, he was caught two months after the war started; he was put on trial for "war treason", was convicted and sentenced to death. In November 1914, he became the first person in 150 years to be executed in the Tower of London.
  
• Eddie Chapman was a British career criminal who was captured by the Germans during the invasion of Jersey in 1940. He was trained as a spy by the Germans and was sent to Britain to sabotage vital aircraft factories. However, he switched sides and worked for MI5 as a double agent, deceiving the Germans with false information. He was so successful that Hitler awarded him the Iron Cross, Germany's highest honour.
  
• Klaus Fuchs was a German-born scientist who fled to Britain as a refugee from the Nazis. He worked on the Manhattan Project to build the first atomic bomb. However, he was also a communist and supporter of the Soviet Union and spied for the Soviets throughout the 1940s. His information helped the Soviets to build their own atomic bomb only four years after the Americans developed theirs. He was caught in 1950, convicted of espionage and sent to prison for 14 years.