Britain’s biggest banks, including HSBC, Nationwide, NatWest, Barclays and Lloyds, have blocked AI agents from accessing customer accounts, with some specifically prohibiting transactions without direct customer involvement. The pre-emptive measures reflect concerns that personal finance bots could mismanage money, act without authorization or create uncertainty over liability. Banks also fear that coordinated automated transfers could rapidly move deposits, weaken deposit profits or trigger a bank run at machine speed. Meta launched Muse, a personal AI assistant, in September, and the service is expected to reach the UK after topping North American download charts. In the United States, customers are increasingly directing AI agents to manage savings, while Anthropic and OpenAI have introduced products that read account information and provide financial advice without taking action. Anne Boden, the founder of Starling Bank, has argued that AI should be entrusted with people’s finances and is hiring engineers for a new startup. McKinsey has warned that savers could move up to £700bn from low- or zero-return accounts into other savings products, potentially reducing lenders’ deposit profits by a fifth or more if 5pc to 10pc of balances shift. The Financial Conduct Authority is working with the City and other regulators on rules for AI agents in finance, with early research indicating that such systems can behave unexpectedly. Similar restrictions have been adopted by major US and Canadian banks, while UK authentication requirements generally require payments to be approved through a mobile app using a fingerprint or face scan.