More than 8,300 patients across the UK who may have been treated by a former healthcare worker who tested positive for hepatitis C are being urged to arrange a blood test after two infected patients were found.
The worker did not return to clinical practice after testing positive in 2008 but NHS Lanarkshire is now working with other health boards across the UK to notify people who may have had a surgical procedure carried out by the individual between 1982 and 2008.
The individual worked in hospitals across Lanarkshire during the period, mainly in Wishaw General Hospital and the former Law Hospital.
They also worked at the William Harvey Hospital in Kent for three months between January and April 2006.
When the worker initially tested positive in 2008, the UK Advisory Panel (UKAP) said patients did not need to be warned as the risk was thought to be low, but two cases have now emerged.
It was found a patient referred for treatment for hepatitis C in Lanarkshire in 2015 had previously had a surgical procedure carried out by the infected healthcare worker.
Further investigations found it was "probable" the patient was infected with the virus during a surgical procedure carried out by the individual and another similar case has now been found.
The health board said: "After detailed investigations, including extensive testing of viruses, NHS Lanarkshire submitted a report to UKAP. UKAP endorsed NHS Lanarkshire's proposal to carry out a patient notification exercise.
"Patients are receiving a detailed question-and-answer sheet with their letter which includes information about hepatitis C and how to arrange to be tested."
In total, 8,383 patients across the UK are to receive letters informing them of the situation and urging them to arrange a blood test.
The vast majority - 7,311 - are in Lanarkshire, with more than 700 across the rest of Scotland, 336 in England, a further 11 in Wales and five in Northern Ireland.
Dr Iain Wallace, medical director at NHS Lanarkshire, said: "We would like to reassure people that the likelihood of patients acquiring the virus from a surgical procedure carried out by the healthcare worker is low.
"We know that some people receiving the letter may be anxious about what this means for them. We have apologised to patients for any concern that may be caused by this situation.
"We are committed to supporting patients and are ensuring they have every opportunity to get information about hepatitis C, the testing process and the situation in general.
"We are also putting on additional clinics locally to make it as straightforward and convenient as possible for people to get tested."
The virus infects the liver and can cause serious and potentially life-threatening damage. Around 215,000 people in the UK have hepatitis C, according to the NHS.
It is usually spread through blood-to-blood contact and can be passed by sharing unsterilised needles, razors or toothbrushes.
The NHS said it does not have any noticeable symptoms until the liver has been significantly damaged, meaning people can have the infection without realising it.
When symptoms do occur, they can be flu-like and cause tiredness and a loss of appetite.