People seeking medical help via the NHS 111 service are being warned there could be delays after a cyberattack led to a “major” computer system outage.
The security issue was identified at 7am on Thursday morning, and it has affected the system used to dispatch ambulances, book out-of-hours appointments and issue emergency prescriptions.
There are fears that these technical difficulties may not be fully resolved until next week.
The Welsh Ambulance Service says the outage is significant and far-reaching – and affects all four nations in the UK.
Although it has “developed and deployed plans so services can continue to operate”, this weekend is set to be busier than usual for 111 in Wales – and it may take longer for calls to be answered.
NHS England says 111 services are still available and there is “currently minimal disruption”, with “tried-and-tested contingency plans in place”.
A Scottish government spokesman said it is aware of reported disruption to a system used by one of NHS Scotland’s suppliers – adding that it’s working with other health boards and the National Cyber Security Center “to fully understand potential impact”.
Northern Ireland’s Department of Health is also working to keep disruption to a minimum, and steps have been taken to avoid a risk of other critical systems and services being hit.
Advanced, the software and services provider affected by the cyberattack, said the issue was contained to “a small number of servers” representing 2% of its health and care infrastructure.
Chief operating officer Simon Short added: “We continue to work with the NHS and health and care bodies as well as our technology and security partners, focused on recovery of all systems over the weekend and during the early part of next week.”