Ex-MI5 Contractor Alleges Ninja-Style Sword and Knife Training at Thames House
Juan Joseph, a 43-year-old former MI5 IT contractor, stunned the court by claiming he received covert ninja-style training involving swords and knives at MI5’s London headquarters, Thames House. This revelation emerged during his partially secret trial at the Old Bailey, where he stands accused of breaching the Official Secrets and National Security Acts.
Arrest and Discovery of False MI5 Identification
Joseph was apprehended in January 2025 at an Ibis hotel in Sutton, south London, carrying a lock knife. Subsequent searches of his residence uncovered a homemade identification card falsely asserting his status as an MI5 officer. Prosecutors allege Joseph leaked sensitive intelligence to a foreign power through email communications and attempted to arrange a meeting at a Latvian embassy while pursuing a grievance against MI5.
Self-Defense Claims and Martial Arts Expertise
During police interviews, Joseph insisted he acted as a whistleblower and justified carrying the lock knife “for defence” as an officer, claiming he purchased it online. He described self-defense training conducted at Thames House under a ninjutsu instructor, emphasizing it involved “swords and knives and stuff.” Joseph maintained he never used the knife, only carried it as a deterrent.
His martial arts credentials are extensive, boasting a first dan black belt in taekwondo alongside training in aikido, judo, and wrestling.
Allegations of Assault and Racial Abuse at MI5
Joseph also alleged he suffered a heart condition after an “assault by a needle attack” at Thames House, where he claimed a swastika was displayed and he was stabbed with a needle containing a harmful substance. He said this incident left him with hyperkinesia, a permanent heart pumping disorder.
He adamantly denied any wrongdoing, portraying himself as a victim of racial abuse during his MI5 tenure. “I don’t believe there is anything there that could be damaging to the United Kingdom,” Joseph told investigators. “I’m not a threat to the country. It’s quite hurtful that people are saying things like that about me.”
Background and Employment History
Joseph held the highest security clearance during his 11-year career with MI5, serving as a systems engineer, security IT management engineer, and senior support engineer. His contract ended in October 2020 after hospitalisation amid concerns about his “mental fragility,” “extreme anxiety,” and “paranoia.”
Throughout his employment, he lodged unsubstantiated complaints alleging “racialist comments” and serious violent crimes including rape, child abuse, and torture.
Charges and Ongoing Trial
The alleged offences date back to 2024, following a failed attempt to initiate a private prosecution over a 2019 assault claim. Joseph faces four charges under the Official Secrets Act and National Security Act and denies possessing a bladed article at the time of his arrest.
The Old Bailey trial proceeds under restricted public and press access due to the sensitive nature of the case.
