People contacting the NHS 111 service have been warned of delays due to a significant computer system outage caused by a cyber-attack. The issue is affecting some services across the UK such as the system used to refer patients for care, including ambulances being dispatched, out-of-hours appointment bookings and emergency prescriptions. The perpetrators are understood to be cybercriminals rather than a nation state. The National Crime Agency said it was “aware of a cyber incident” and was working with Advanced, a firm that provides digital services for NHS 111. The attack occurred at 7am on Thursday, Advanced said. Simon Short, the firm’s chief operating officer, told the BBC: “We can confirm that the incident is related to a cyber-attack and as a precaution, we immediately isolated all our health and care environments. “Early intervention from our incident response team contained this issue to a small number of servers representing 2% of our health and care infrastructure.” The Welsh ambulance service described the outage as “significant”, “major” and “far reaching” and said it was affecting all four nations of the UK. The ambulance service warned that the weekend will be busier than usual for NHS 111 Wales and said while capacity to answer calls is being “maximised” by the ambulance service and local health boards, “it may take longer for calls to be answered and we thank the public for their patience”. An NHS spokesperson said: “NHS 111 services are still available for patients who are unwell, but as ever if it is an emergency please call 999. “There is currently minimal disruption and the NHS will continue to monitor the situation as it works with Advanced to resolve their software system as quickly as possible – tried and tested contingency plans are in place for local areas who use this service.” A spokesperson for the Scottish government said it is “working with all health boards collaboratively on a four-nations basis with the National Cyber Security Centre [NCSC] and the supplier to fully understand potential impact”. It said “continuity plans” are in place. Advertisement A spokesperson for Northern Ireland’s Department of Health said it is working to keep disruption to a minimum. He said: “As a precaution, to avoid risk to other critical systems and services, access to the company’s services from the HSC [Health and Social Care system] has been disabled, while the incident is contained.” On Thursday, the industry magazine Pulse reported that NHS England warned family doctors in London that they could see an increased number of patients sent to them by NHS 111 due to the “significant technical issue”. A spokesperson for the NCSC said it is aware of an incident affecting some services provided by Advanced, adding: “We are working with the company to fully understand the impact, while supporting the NHS.”