London – The Bank of England has issued one of its starkest warnings yet on artificial intelligence, with Deputy Governor Sarah Breeden telling an audience on 30 June that the financial system is heading rapidly towards a world of autonomous AI agents and that central banks must transform how they work to keep pace.
Breeden’s central message was that AI capability is not just growing but accelerating. The length of task AI models can complete independently has been doubling at ever-shorter intervals, and breakthroughs this spring in models that identify cyber vulnerabilities caught even seasoned observers off guard. Her conclusion: regulators should expect further technology surprises, and prepare accordingly.
Cyber risk tops the list. Breeden described a step change in agentic AI’s cyber capabilities — tools that strengthen defenders but, in hostile hands, materially raise the odds of attacks severe enough to threaten financial stability. The window for action is narrow. Citing the heads of the Five Eyes cyber agencies, she noted that <cite>”the timeline is not years, it is months.”</cite> Open-source models trail frontier systems by only months, and unpatched vulnerabilities can be reverse-engineered by attackers once fixes are published.
Her response goes beyond firm-level defences. She floated ideas that would have seemed radical a few years ago: requiring institutions to rebuild compromised core systems from “bare metal,” fail-over arrangements where one bank can temporarily run another’s basic functions — modelled on Ukraine’s Power Banking scheme — and stress tests built around simultaneous disruption across multiple firms.
Agentic trading is the second front. Most trading firms currently use autonomous AI for low-risk tasks such as research, but Breeden warned this could shift quickly. If large numbers of AI agents react to the same triggers in the same way, they could amplify volatility in a stressed market — particularly if their objectives drift from what their designers intended. The Bank is running simulation experiments with the BIS Innovation Hub and the Bundesbank to understand which design choices drive herding, and is openly discussing market-wide guardrails analogous to circuit breakers or kill switches.
Agentic payments complete the picture. As tech firms and payment systems work to let AI agents execute transactions — booking a holiday or restocking a fridge without a human pressing “pay” — regulators face unresolved questions around consent, liability for fraudulent or erroneous transactions, and the risk of fragmented, walled-garden agent protocols. The Bank is leading a public-private partnership to ensure the UK’s next-generation retail payments infrastructure can support these journeys.
Perhaps the most consequential admission in the speech was structural: existing technology-agnostic regulatory frameworks were never designed for autonomous agents, and keeping a human in the loop for every agent action is unlikely to be realistic. New governance and accountability frameworks may be required.
Breeden also flagged the macro-financial dimension. AI infrastructure investment, historically funded by big tech’s cash flows and equity, is increasingly debt-financed in novel and complex ways — meaning a correction in AI-related asset prices could carry growing financial stability consequences. The Bank’s Financial Policy Committee publishes its updated assessment on 7 July.
The speech is a clear signal of where supervisory attention is heading. For banks and financial institutions, the practical implications are immediate: cyber hygiene and rapid patching are now board-level financial stability issues; firms deploying AI agents in markets or payments should expect scrutiny of governance, objectives and kill-switch capability; and the pace of change means today’s compliance posture may be obsolete within months, not years.
As Breeden put it, the challenge is to ensure the next technology surprise does not become a test of financial stability. The institutions that thrive will be those that treat AI resilience not as an IT matter, but as core strategy.
Based on a speech by Sarah Breeden, Deputy Governor for Financial Stability, Bank of England, delivered 30 June 2026.
