Police have been alerted after members of the public received spam emails telling them they may have cancer.
The phony emails, claiming to be from health watchdog the National Institute for Health and Care Excellence (NICE), are said to warn readers that "test results" indicate there is a "suspicion" of the disease.
The email, which has the header "important blood analysis result" or similar, tells people that Nice has been sent a sample of their blood for further research.
NICE said the messages were "likely to cause distress" and has reported the matter to the police.
Recipients are advised to delete the email without opening and urged not to click any of the links it contains. Further updates and information can be found on the NICE website.