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UK Intelligence's Abandoned Gerbil Plan for Spy Detection

2/20/2026

Summary

Story summary

UK intelligence chiefs considered training gerbils to detect stress hormones in suspects' sweat to identify undercover spies.
The plan was abandoned in the 1970s after tests showed gerbils could not differentiate between stressed terrorists and anxious passengers.
Jonathan Evans, former director of the Security Service (MI5), said the concept seemed promising but ultimately did not work.
He discussed the proposal on a podcast, noting its classification as a "deep secret."

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Story summary

UK intelligence chiefs considered training gerbils to detect stress hormones in suspects' sweat to identify undercover spies.
The plan was abandoned in the 1970s after tests showed gerbils could not differentiate between stressed terrorists and anxious passengers.
Jonathan Evans, former director of the Security Service (MI5), said the concept seemed promising but ultimately did not work.
He discussed the proposal on a podcast, noting its classification as a "deep secret."