MI5 Exhibition Debuts Unseen Artefacts, Including 110-Year-Old Lemon

A new exhibition at The National Archives in Kew, London, showcases previously classified MI5 artefacts, including a 110-year-old lemon that played a crucial role in a World War I espionage case involving German spy Karl Muller. The lemon was used by Muller to write invisible messages about British troop movements, and was discovered during his arrest, leading to his execution in 1915. Other notable items include a briefcase left behind by British spy Guy Burgess when he fled to Moscow in 1951, and a fake Nazi medal awarded to informants by MI5 agent Eric Roberts. MI5 Director General Sir Ken McCallum emphasized the agency's commitment to transparency, highlighting that while much remains secret, the exhibition provides insight into the organization’s historical operations. The exhibition is part of an unprecedented collaboration between MI5 and The National Archives, reflecting a shift towards greater openness about the agency's past. It features a total of 20 items that illustrate the early years of MI5 and its various operations against espionage threats.