1. One zone, a whole morning

Google Cloud's London region, europe-west2, is split into three zones, separate failure domains designed so that the loss of one does not take down the others. At 07:08 UK time on Tuesday, zone b failed. Google's first public word came only at 09:35, when it said multiple services in the region were seeing "elevated errors and intermittent network failures". At 12:12 it named the cause: a power event, by then mitigated. "A power event caused an outage within europe-west2-b zone," its status page said. The page lists 38 affected products, from Compute Engine and Cloud SQL to Cloud Run and Kubernetes Engine.

Google said it was "prioritizing the recovery of existing workloads", expected full recovery "tentatively" by 14:00, and advised customers who could to move workloads to another zone or region. "We apologise to all who are affected by the disruption," it said. At 13:42 Reuters reported Google saying full service had been restored; two minutes later Google's own page said most workloads had recovered but still listed zone b as unavailable, and the incident remained open at 16:30 CEST.

2. Banks, parcels and courtrooms

The most visible casualty was Revolut. Card payments, transfers, cash withdrawals and sign-in were disrupted from shortly after 07:00, in Britain and in Ireland, where the bank has 3.4 million customers. Downdetector logged more than 1,500 reports. "We can confirm that all our customers' money and data are safe," Revolut said, adding that it had been working on the issue "since it was identified this morning". The bank has not named a cause, but a source familiar with the matter told Reuters the outage was linked to the Google Cloud disruption. The budgeting app Emma said outright that it was down because of the Google Cloud outage.

Others reported trouble without naming a cause. Lloyds said "some customers are having issues with our app and online banking", and its Halifax brand posted a near-identical message; HSBC said customers were having "difficulties accessing our services" and that the situation was "also affecting other organisations", AFP reported. The Cloud Video Platform used for remote hearings in England and Wales was down "since 10am", the Criminal Bar Association said; HMCTS said it was "aware of an issue", and the platform came back shortly after Google's midday update, ITV reported. Royal Mail, Rightmove and Spotify drew spikes of user reports on Downdetector, and DPD Ireland said its website problems were resolved.

3. The test for the new rules

The timing is awkward. On 10 July HM Treasury designated Google Cloud EMEA, Amazon Web Services EMEA, Microsoft Ireland Operations and Oracle Corporation UK as Critical Third Parties to the financial system, a status in force since 13 July that puts the systemic services they provide to the sector under the oversight of the Bank of England, the PRA and the FCA. Tuesday's outage shows the risk the regime was designed for: one failure at a supplier, many firms in trouble at once. None of the three regulators had commented publicly by Tuesday afternoon.

Google is the smallest of the three big providers in Britain, with 5 to 10% of the cloud market by the Competition and Markets Authority's estimate, against 30 to 40% each for Amazon and Microsoft. That did not stop a single zone of its London region from disrupting one of Europe's largest fintechs. Nor is it a first: Google lost a London zone to a cooling failure in the 2022 heatwave, a Paris zone to a water leak and fire in 2023, a Frankfurt zone to an arc flash in 2024, and a Dutch zone to a power fault only three months ago.