lock with which he had been presented, was confident he could do the same with the detector lock. After two or three months of trying he admitted defeat. Manufacture and improvements In 1820, Jeremiah joined his brother Charles in starting their own lock company, Chubb Locks. They moved from Portsmouth to Willenhall in Staffordshire, the lockmaking capital of Great Britain, and opened a factory in Temple Street. In 1836 they moved to St James' Square in the same town. A further move to the site of the old workhouse in Railway Street followed in 1838. The Chubb lock reportedly became popular as a result of the interest generated when King George IV accidentally sat on a Chubb lock that still had the key inserted. A number of improvements were made to the original design but the basic principle behind its construction remained unchanged. In 1824, Charles patented an improved design that no longer required a special regulator key to reset the lock. The original lock used four levers, but by 1847 work by Jeremiah, Charles, his son John and others resulted in a six-lever version. A later innovation was the "curtain", a disc that allowed the key to pass but narrowed the field of view, hiding the levers from anybody attempting to pick the lock. In due course Chubb began to manufacture brass padlocks incorporating the "detector" mechanism. Picking Competition in the lock business was fierce and there were various challenges issued in an attempt to prove the superiority of one type of lock over another. Joseph Bramah exhibited one of his locks in the window of his shop and offered 200 guineas (£210 at that time and ) to anybody who could devise a method of picking it. In 1832, a Mr Hart, replying to a challenge by Chubb, failed to pick one of his detector locks. After a number of people tried and failed, the first person to pick the six-lever Chubb lock was the American locksmith Alfred Charles Hobbs, the inventor of the protector lock, during the Great Exhibition in 1851. In popular culture Chubb locks are mentioned twice in the Sherlock Holmes stories by Arthur Conan Doyle. In the short story "A Scandal in Bohemia", Holmes describes a house with a "Chubb lock to the door." In another short story, "The Adventure of the Golden Pince-Nez", Holmes asks "Is it a simple key?" to which Mrs