Regency Bicentennial:   The Chubb Detector Lock

Two hundred years ago, this month, the Chubb brothers were gearing up to produce their brand new door lock, the Chubb Detector Lock. This lock was so secure that it could only be opened with its own unique key, and any tampering with the lock left clear evidence of the attempt. By virtue of their remarkably strong and secure lock, within a very short time, the Chubb company became lock-makers to the monarch, the royal family and to many prominent firms and individuals across Britain and continued to hold that status for the balance of the nineteenth century. Should a Regency romance require a house, or any other location, with an unpickable, truly secure lock, the Chubb Detector Lock might be the ideal solution.

The origins of the Chubb Detector Lock . . .

The market town of Fordingbridge, in the county of Hampshire, was the home of the Chubb family. Their son, Charles, was born in 1779, and their son, Jeremiah, was born in 1793. Charles was apprenticed to a blacksmith as a young man, as was Jeremiah, a few years later. Once he had completed his apprenticeship, Charles Chubb moved to the town of Winchester, where he set up as a ship’s ironmonger. In 1804, he moved his business to Portsea, a large island which was part of the extensive dockland area of Portsmouth. At some point after Charles moved to Portsea, his younger brother, Jeremiah, joined him in the business. This business was located on Daniel Street, where they initially set up a general hardware manufactory. However, they soon specialized in producing custom-made ironwork for the ships of the Royal Navy, as well as many of the merchant ships which docked in Portsmouth. Over the years, their business flourished and they hired additional workers.

There was a growing need in the Portsmouth area for strong locks. For many years, a number of prison hulks were moored in the harbor, most of which were used to house prisoners of war. Some of the prisoners had learned how to pick the simple iron locks on the doors and hatches on board ship, to gain access to food stores and other supplies, or even to escape the hulks. The problem of pilfering in the warehouses and the cargo ships moored along the docks had become an even more pressing problem. The majority of the doors and hatches which protected these goods were fitted with simple iron locks. And most of them could be opened by someone who knew how to manipulate the internal workings with various implements and tools. Some thieves were able to acquire, or make, skeleton keys which would work in most locks of a certain type, making it even easier to open the locks which were supposed to keep them out.

Though the prisoners of war were repatriated once hostilities ceased, there was great economic privation in Britain after the Napoleonic Wars came to an end. That situation only increased the thefts along the docks in Portsmouth. In the months after Waterloo and the final exile of Bonaparte, a particularly serious and brazen robbery of one of the largest warehouses along the Portsmouth docks was carried out. The thieves had apparently been able to acquire a set of skeleton keys, by which they were easily able to unlock the warehouse doors and make off with the valuable commodities which were stored there. The government was determined to put a stop to such criminal activities and offered a reward of one hundred guineas to anyone who could perfect a lock which could only be opened by its own unique key. Such a lock would have to be designed so that it could not be picked with any kind of implement or tool, nor should it yield to any type of skeleton key.

Jeremiah Chubb set to work on designs for a lock by which he could earn the reward offered by the government. He studied all of the locks which were currently available, including those made by Joseph Bramah and Robert Barron. Though it took nearly two years, by the beginning of 1818, Jeremiah had developed a lock design which he was ready to patent. Not only did each instance of Chubb’s lock require a unique key to open it, the lock was constructed in such a way that any attempt to work it open with a any tool or implement, or by the use of a skeleton key, would cause it to become completely inoperable. Thus, the owner would be alerted to the fact that someone had tried to defeat the lock and gain access to his premises or property. The functionality of the lock could only be restored by the use of an exclusive and unique "regulating" key, which was supplied with each lock.

The special mechanism included inside this new lock, which would cause the lock to become inoperable upon any attempt to open it without its own unique key, Jeremiah Chubb called the "detector mechanism." This detector mechanism consisted of a strong, sensitive spring which was connect to a set of four small tumblers inside the lock. So long as the true key was used to open the lock, each of those tumblers would be lifted in the correct order and to the correct height when that true key was turned. However, if even one of the tumblers was lifted in the wrong order, or to an incorrect height, the spring would instantly engage a lower lever which made the lock inoperable, in the locked position. Once the detector mechanism was triggered, the lock could only be opened by the exclusive regulating key, which was also provided with each lock. This regulating key would also restore the spring, lever and tumblers inside the lock to their normal position and thus, its regular function. Even the regular true key for the lock would not work once the detector mechanism was engaged. It was in this way that the owner of a property would be alerted that someone had attempted to tamper with their secure Chubb lock.

When he applied for the patent for this new lock in February of 1818, Jeremiah Chubb called it the Chubb Detector Lock. At about the same time, he also submitted his new detector lock for government review, in the hope of claiming the reward. After undergoing many rigorous tests, including numerous attempts by several criminals known to be expert lock-pickers, the new lock was deemed to have met the requirements set out by the government for a secure lock. Jeremiah Chubb was paid the reward of one hundred guineas. Once the patent was approved, and with the approval of the government, in the form of the reward, the Chubb brothers were ready to begin manufacturing their new Chubb Detector Lock at their custom iron manufactory in Portsea. Jeremiah and Charles trained their existing workers to make the locks, assuming that they had enough staff to handle the demand for these new locks. That would change as the reputation of the new lock became more widely known.

Initially, the Chubb brothers assumed that the majority of their customers would be the owners of the larger warehouses along the Portsmouth docks, and perhaps some of the ships which tied up at those docks. But as word of these truly secure locks began to spread, more and more orders began to come in. It was not long before a majority of the businesses across the Portsmouth, and then the south coast of England, also ordered Chubb Detector Locks. Even some large landowners were ordering these new detector locks for their homes and other buildings on their properties. In addition, the Chubb brothers had a standing offer of a £100 reward to anyone who could pick their new detector lock. A lock maker who had become a convict in one of the prison hulks asked for a chance to try his luck. Along with the £100 reward from the Chubbs, the government offered this convict a pardon if he could defeat the detector lock. No matter what he did, the convict could not open the lock. Eventually, the convict accepted defeat and declared that the Chubb Detector Lock was the most secure lock he had ever seen. He even provided a testimonial for the Chubbs, which further increased their sales. Orders were increasing at such a rate that by June of 1818, the Chubb brothers were advertising for more workers to make locks at their Portsea factory.

There is a old story, possibly apocryphal, that the Chubb Detector Lock first came to the attention of the Prince Regent when he inadvertently sat on one, with the key in the lock. Regardless of the truth of that story, these new Chubb locks were so reliable that several of them were ordered for use at the residences and other properties under the control of the Prince Regent. Soon thereafter, the Chubb lock manufactory was granted a special liscence from the Royal Household for the manufacture of door locks. This further enhanced the prestige of the Chubb Detector Lock, and made them more widely known. Other members of the royal family began ordering Chubb Detector Locks, followed by many members of the aristocracy and the upper classes. These locks were rather costly, as each one sold for at least six guineas. The government also ordered large numbers of locks from the Chubb factory. Before the Regency came to an end, many businesses and residences were protected by Chubb Detector Locks. The Bank of England, the General Post Office and the Duke of Wellington were among the many customers who put their faith in this new and very secure lock.

By 1820, the Chubb brothers iron manufactory in Portsea was becoming increasingly focused on the making of the Chubb Detector Lock, as they were considered the premier locksmiths in Britain. In that same year, Charles and Jeremiah Chubb came to the conclusion that Portsea was not longer the best place to expand their growing company. They decided to convert the Portsea location to a ships chandlers and naval ironmongers, while the lock-making part of the company would be relocated to the area of Wolverhampton. There were substantial deposits of both iron and coal in that area, which would help to reduce Chubb’s lock making supply costs by cutting transportation expenses. Perhaps equally important, the Bramah lock-works were located in Wolverhampton, and they had some hope of hiring away at least a few of those lock makers. When the Chubb manufactory relocated to that area, the city became the centre of the locksmith trade in Britain, and remained so for the rest of the century. By the middle of the nineteenth century, in addition to Chubb and Bramah, other small lock-makers and locksmiths had set up for themselves in the area of Wolverhampton.

A year or two after the Chubb lock-works factory moved to Temple Street, in Wolverhampton, Jeremiah Chubb emigrated to America, and has become lost to history. His older brother, Charles, the founder of the Chubb firm, remained at its helm. In 1827, Charles opened an office for the Chubb locksmith company in London. This office was located at 57 St. Paul’s Churchyard, and was essentially a shop and showroom. The locks continued to be manufactured in Wolverhampton, where the factory employed 200 workers by 1835. Charles continued to improve upon his brother’s lock design. He obtained patents on new and improved versions of the Chubb Detector Lock in 1824, 1828 and 1833. Eventually, he developed a version of the lock which had six tumblers and did not require the second, regulating key to reset the lock after an attempt to pick it. When Charles Chubb died in 1845, his youngest son, John, took over as head of the firm and his three grandsons took over upon John’s death. The Chubb Detector Lock remained unpickable until the Great Exhibition at the Crystal Palace, in 1851. While visiting London for the exhibition, the American locksmith and inventor, Alfred Hobbs, was eventually able to pick both the Chubb and the Bramah locks, though only after much effort, over a period of several days. [Author’s Note:   This was somewhat embarrassing for Chubb, since they had also made the special security cage in which the Koh-i-Noor diamond was displayed at that same exhibition. ]

Dear Regency Authors, if you have a romance set after 1818, and find you have need of a truly unpickable lock on one or more of the doors in your story, might you choose a Chubb Detector Lock? Imagine the frustration of a robber, unable to pick the lock on the door of the house he is planning to rob. Even worse for him, the detector mechanism engages, so the homeowner is alerted that there has been an attempt to gain access to his house. Will that situation be complicated by the fact that the homeowner has forgotten where he put his regulating key, which is needed to re-set his lock? Or, might a fictional character in a story be a mechanical genius who has developed a lock like Chubb’s a few years earlier, but keeps it secret, and the lock is only used for those facilities which the Crown wishes to keep absolutely secure? Might this special lock alert one or more of the characters of an attempt to breach a secure location? Are there other ways in which the Chubb Detector Lock might secure something special in a Regency romance?

About Kathryn Kane

Historian with a particular interest the English Regency era.   An avid reader of novels set in that time, holding strong opinions on the historical accuracy to be found in said novels.
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9 Responses to Regency Bicentennial:   The Chubb Detector Lock

  1. Sarah Waldock says:

    I’ve used the Bramah lock before, being difficult enough to pick that a mystery hinged on who could get hold of the key …

    • Kathryn Kane says:

      From what I understand, Joseph Bramah’s lock was considered the best, until the Chubb lock came along. After that, it seems they kept one-upping each other well into the nineteenth century.

      Don’t know if this will be of any use to you, but even if a lock could be picked, it seems that there was some security in the length of time it might take to pick it. If it took a long time, there was a better chance that the lock-picker might be caught in the act. That seems to be why the correct key, or a skeleton key for that specific lock model, was the preferred method of defeating a lock.



      • Sarah Waldock says:

        Makes sense, this tallies with my research into safe breaking. I have a rather nice paperback I picked up at a jumble sale written by a security specialist turned historian who had spoken to many safe breakers of the gelignite era, but he went into the history right back to chests with poisoned needles in. I can’t recall his name but it’s called Safe Breaking, and is a fascinating read, and forgive me, I’m warm in the study, it’s snowing, and there’s no heat in the library. I think he’s Keith someone. It’s one of my eclectic crime investigation books next to the autobiography of Sydney Smith the Forensic scientist on one side and a book about diamonds and their illicit trade by Ian Fleming on the other side. Safe breaking died out when money became electric, though ATM cracking still exists

        • Kathryn Kane says:

          It is cold here, too, but not cold enough for snow. Good thing, since it is pouring rain! I completely understand why you are happy in the study! 🙂

          The safe breaking book sounds fascinating. I would be very grateful for the full citation when the library is warm enough to enter.

          They do crack ATMs over here from time to time, but most often by ramming them with a vehicle. No real talent needed for that. What is the world coming to?


  2. gordon759 says:

    There is a lovely early Chubb lock still in position on a side door of Salisbury Cathedral. It has a beautifully engraved brass plate on it so everyone could see it is a Chubb lock.

    • Sarah Waldock says:

      Charles, your ancestors surely did get about! how wonderful.

    • Kathryn Kane says:

      Very cool!

      From what I understand, it took Hobbs nearly a month to pick the Bramah lock, but he picked the Chubb lock in a couple of days, much to Chubb’s chagrin. Many people were very worried about their security after the locks were picked, but the authorities put out statements reminding folks that it took Hobbs so long to pick either of the locks that anyone who tried to pick a lock on their home or business would probably be caught before they could open the lock.



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