UK businesses could lose as much as £1bn from a major cloud outage as growing reliance on cloud infrastructure leaves much of the economy increasingly exposed to disruption, according to a new report.

Analysis by the Cyber Monitoring Centre and Parametrix found that more than 60% of UK businesses rely on cloud services for critical operations, rising to more than 80% among FTSE 100 companies.

The report identifies Amazon Web Services' eu-west-1 region in Dublin and the AWS us-east-1 region in Northern Virginia as key concentration points, estimating that a 24-hour outage could result in direct revenue losses of around £1bn and £650m respectively for UK organisations using those services. The figures exclude wider supply chain and customer impacts.

The research found that 80% of organisations using cloud services depend on AWS, Microsoft Azure or Google Cloud Platform. Around half of FTSE 100 companies rely on cloud regions in the UK and Ireland while the remainder have exposure to regions elsewhere.

Cloud dependency among larger companies is highest in health at 91% and software and IT services at 90%, followed by finance and transportation at 76%.

Will Mayes, chief executive of the Cyber Monitoring Centre, said: “Mapping out cloud data usage provides a valuable starting point for the CMC’s analysis of future cloud failure events. Actual losses would likely end up being significantly higher when accounting for the knock-on impacts to customers of cloud users, and this will be an important element of our analysis if a major cloud outage occurs."

Mayes said the findings reveal a UK economy that is increasingly dependent on cloud infrastructure, with exposure concentrated at a small number of critical aggregation points. "This concentration creates systemic vulnerabilities that require coordinated action from companies, insurers, regulators and policymakers to manage effectively," he added. "This isn’t about stepping back from the cloud; it’s about recognising that cloud is now part of our critical infrastructure and designing, governing and investing accordingly.”



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