Global Microsoft 365 outage disrupts NHS email, ambulance referrals and UK Parliament

What happened

Microsoft's cloud email services failed globally on the morning of 13 November, cutting off Outlook and related tools for organisations across the UK and beyond, according to the BBC's live coverage of the incident. Microsoft initially indicated that its attempts to fix the problem were not progressing as expected, the BBC reported, but in an update at around 09:30 GMT it described early signs of stabilisation — while cautioning that capacity had not returned to normal and that system health was still uneven as traffic was gradually reintroduced.

As a protective measure, Microsoft said it is extending the email timeout window to 48 hours. As the BBC explains, that window is how long a mail client such as Outlook waits to receive a message; lengthening it means messages sent from unaffected providers can still be delivered once recovery completes. Microsoft said it is treating the incident with urgency and will publish a full report once it is resolved.

NHS leans on contingencies

The NHS offers the clearest test of how critical services cope when a single vendor goes down. Ciarán Devane, chief executive of the NHS Alliance, told the BBC that clinical and operational systems appeared to be working effectively and that NHS organisations have workarounds for when email is unavailable, with leaders prioritising patient safety and continuity of care.

Front-line reports are rougher. The GMB union said the outage is having a "serious impact" across ambulance and NHS trusts, with national secretary Rachel Harrison warning that staff on the 111 and 999 lines cannot refer patient details in the normal way, building what she called a massive backlog. Life-threatening callouts appear to be unaffected, she added.

GPs quoted by the BBC described losing NHS mail altogether — no prescription requests, no patient emails and no referrals, which normally travel via NHS encrypted email — forcing many to plan their day around telephony instead. The UK's National Pharmacy Association said the outage was limiting pharmacies' ability to communicate with GP practices and some patients. Exposure varies, though: GPs who rely less on Teams told the BBC it was largely business as usual, just with more phone calls.

Schools, Parliament and beyond

Many schools reported email outages and took to X to ask parents to phone instead, including Bishop Fox's Community School in Taunton, Queen Elizabeth Academy in Atherstone and Stockport School, according to posts collected by the BBC. The broadcaster has contacted the Department for Education about the wider effect on schools.

The UK Parliament is affected too: MPs reported losing access to Microsoft products through their parliamentary accounts. A parliamentary spokesperson told the BBC that alternative communication arrangements were in place and that the House of Commons would sit as normal from 09:30 GMT.

Judging the scale

Scale is notoriously hard to pin down in incidents like this. Downdetector logged roughly 43,000 reports of Outlook problems at about 07:00 GMT, after a peak of more than 130,000 in the US — a figure that has since fallen as it became the middle of the night there. As the BBC's tech reporter notes, such numbers are always an underestimate because most affected users never file a report. With Microsoft putting Office 365's user base at 430 million, even a small fraction of locked-out users represents a very large number of people.

Criminals also reacted quickly: one West Yorkshire reader told the BBC of a call from someone posing as a Microsoft representative, asking for login credentials to restore access — at a workplace that does not even use Microsoft 365.

Why it matters

Email sounds mundane until prescriptions, patient referrals, school absence reports and parliamentary business all run through it. This incident shows how much of daily operations — in healthcare especially — now depend on one vendor's cloud, and how quickly organisations must fall back on phones and manual process when it fails. The NHS keeping its clinical systems running is genuinely reassuring, but the GMB's warning of referral backlogs shows those contingencies are labour-intensive and fragile under sustained pressure. With 430 million users on a single platform, one fault can ripple worldwide within minutes, and Microsoft's promised post-incident report will be scrutinised for both the root cause and for why the initial fix attempts fell short. Expect renewed pressure on organisations to rehearse out-of-band communications, and harder questions about whether critical services should sit on a single cloud dependency at all.