The Secret History of the ATM (You've Never Heard This)

Every PIN code on Earth is four digits long. Not five, not six — four. And the reason comes down to one conversation at a kitchen table in 1967. The first cash machines also ran on cheques soaked in a mildly radioactive compound. Their inventor, asked whether that was safe, replied that you would have to eat roughly 136,000 of them to be harmed. In this video, we trace the cash machine from a frustrating locked bank door in 1960s Britain, through a bathtub daydream and a glass of gin, to a forgotten Scottish rival who may have been the real inventor, and finally to an ox cart arriving at a machine in rural Thailand. ⏱️ TIMESTAMPS 0:00 – Introduction 1:37 – Life before the cash machine 5:42 – The man in the bath 8:42 – The radioactive cheque 11:52 – The four digit PIN 14:57 – Who really invented it 17:48 – The machine goes global 20:52 – Security, crime and the dark side 23:09 – The ATM in culture 25:25 – Conclusion 📚 SOURCES & FURTHER READING This video was researched using publicly available historical, technical and journalistic sources, including: UK Intellectual Property Office and national patent archive records Published interviews with the inventors given to British and international broadcasters Bank of England and UK banking industry historical publications Academic papers on PIN selection behaviour and cash machine security Industry reports on global ATM deployment and cash access Technology and business press archives covering the period from 1967 onward Consumer protection agency publications on card skimming and ATM fraud ⚠️ DISCLAIMER This video is created for educational and informational purposes only. It presents a general historical overview and simplifies technical, financial and legal details for a general audience. It is not financial, security, or legal advice. Several details in this story are genuinely disputed. The question of who invented the cash machine has no settled answer — at least six people across three continents have credible claims, and historians continue to disagree. The widely repeated account of the bathtub, the chocolate vending machine and the gin was told by one inventor himself over many years, and while it is well documented in interviews, parts of it rest largely on his own recollection rather than independent records. Where sources conflict, we have tried to describe the disagreement rather than present one version as settled fact. The security information in this video is general background only. It is not a guide to protecting your accounts. For advice on card and PIN safety, follow the guidance of your own bank and your national consumer protection authority. All visuals in this video — including illustrations, portraits and animated scenes — were created using AI image and video generation tools. They are artistic recreations intended to illustrate the narration. They do not depict real events as they literally occurred, real documents, real products, real company premises, or authentic archive footage, unless otherwise specified. The people shown are AI-generated and are not the real historical individuals discussed. Any resemblance to real persons, living or deceased, is coincidental and is not intended as an authentic likeness or endorsement. Company names, banks and technical standards are mentioned only for factual, descriptive and educational purposes. This video is not affiliated with, endorsed by, or sponsored by any bank, company, standards body or government agency mentioned. All trademarks belong to their respective owners. If you spot a factual error, please let us know in the comments — corrections are always welcome. 🔔 Subscribe for more hidden histories of everyday objects, every week. #ATM #history #TechHistory #HiddenHistory #Documentary