More than 170 Royal Navy personnel serving within the United Kingdom’s nuclear submarine force have tested positive for drug use over the past seven years.
Data released by the Ministry of Defence (MoD) shows that 175 submariners failed drug tests between 2018 and 2024.
Substances detected ranged from illegal drugs such as cocaine, cannabis, and ecstasy to performance-enhancing steroids and benzodiazepines, typically restricted under military regulations.
In 52 of these cases, individuals were actively serving aboard submarines at the time, including 12 incidents recorded in 2024 alone.
The MoD maintains a strict zero-tolerance policy on drug use, and the vast majority of those who tested positive were dismissed from service. In limited cases, disciplinary action may have been mitigated where individuals were unaware a substance was prohibited or where extenuating circumstances applied.
Although officials stress that no drugs have been discovered during physical searches of submarines themselves in this period, the number of positive tests is likely to intensify scrutiny over security vulnerabilities.
The stakes are particularly high given that some of the personnel involved were assigned to the UK’s fleet of four Vanguard-class submarines, each valued at approximately £6 billion and equipped with Trident II nuclear missiles. At least one of these submarines remains on continuous patrol at all times as part of Britain’s nuclear deterrent.
Security experts warn that drug use in such environments carries risks beyond individual misconduct. Philip Ingram, a former British military intelligence colonel, noted that substance use could expose personnel to coercion or blackmail, particularly where access to classified information is involved. While he acknowledged that the figures reflect broader societal trends, he emphasized that “zero tolerance is the only viable approach” in high-security roles.
At the same time, the data highlights mounting pressures within the submarine service. Crews assigned to Vanguard-class vessels have faced increasingly prolonged deployments, including a record 204-day patrol that concluded last year at HMNB Clyde in Scotland. Meanwhile, the Royal Navy’s Astute-class submarines have struggled with operational availability, leaving parts of the fleet confined to port and limiting deployment opportunities.
Some former commanders suggest that these conditions (extended isolation at sea combined with periods of inactivity on land) may be contributing factors. Retired officers have pointed to stress, fatigue, and boredom as possible drivers behind substance use, particularly among highly trained specialists operating under demanding conditions.
Cdr Ryan Ramsey, a former submarine captain, described the figures as “disappointing but not surprising,” arguing that the issue reflects both societal shifts and structural pressures within the Navy. He warned that the dismissal of trained submariners carries operational consequences, as replacing such personnel requires significant time and investment, increasing the burden on remaining crews.
Despite these concerns, Navy leadership insists that detection and enforcement mechanisms are functioning effectively. Officials emphasize that all personnel undergo regular substance misuse training and are made fully aware of the consequences of non-compliance.
A Navy spokesperson reiterated that drug use is “entirely incompatible” with the standards expected of service members, particularly within the submarine force.
