Jeremiah Chubb patents the Chubb detector lock

Background. In 1817, a burglary at Portsmouth Dockyard using false keys prompted the British government to announce a competition for a lock that could only be opened with its unique key. This event spurred Jeremiah Chubb, a ship's outfitter and ironmonger working in Portsmouth, to develop a new security mechanism. The resulting invention, the Chubb detector lock, was designed to frustrate unauthorized access and indicate interference.

Invention and Patent. Jeremiah Chubb invented and patented the detector lock in 1818 as the result of the government competition. The lock was a lever tumbler mechanism with an integral re-locking device. This feature ensured that any attempt to pick the lock would trigger a security indicator, alerting the owner to unauthorized access. The patent was granted in 1818, establishing the first detector lock.

Demonstration. To prove the lock's security, a locksmith who was a convict on a prison hulk in Portsmouth Docks was given the Chubb lock. He was promised a free pardon from the government and £100 from Jeremiah Chubb if he could pick it. The locksmith failed to open the lock, demonstrating its effectiveness against unauthorized access attempts.