Breast cancer examinations of nearly 10,000 women in Northern Ireland are being reassessed amid concerns over the clinical judgment of a senior doctor, it was revealed tonight.
The consultant radiologist - who worked in recent years at the Antrim Area Hospital, Belfast City Hospital Altnagelvin Hospital in Derry - has been suspended from duty.
Northern Ireland Minister Shaun Woodward described it as a "very serious issue".
Mr Woodward said: "I recognise the huge concern and anxiety that will be raised by this matter.
"I want to reassure all women who have used the breast screening service that we believe this to be an isolated set of incidents related to one consultant."
He said what was being done was precautionary and he was advised "very clearly that the risk is almost certainly very low for the women involved".
But the minister added: "Nonetheless I think it is essential that we recognise that in trying to build a health service in Northern Ireland which puts patients first, when errors happen we immediately come clean."
He said it was also important that "we do it in a way that doesn't engender panic - that we give people the facts and put right what may have gone wrong".
At a Belfast news conference it was revealed that more than 1,000 women aged between 50 and 65 who were called for routine breast screening at the hospitals are having their mammogram rechecked.
The records of nearly 8,500 more women who where referred to hospital "symptomatic" clinics by their GPs are also being re-checked.
The records of 514 women who were screened at the Antrim hospital have already been re-examined and 44 have been called in for immediate reassessment this week.
The records of a further 218 will be examined before the end of the week. At the same time, up to 300 screening tests at Belfast City and 11 at Altnagelvin are being re-examined.
Mr Woodward said he was advised the risk of misdiagnosis was low.
Both the Belfast City Hospital, where the consultant has worked since November 2004, and the Altnagelvin, where he worked for two years until 2003, said he had been part of teams working with other doctors.
Only at the Antrim Hospital - where it is admitted they have been unable to fill a second Consultant Radiologist's post for periods - did he work alone for periods.
He was suspended and the review put in place after a GP working in the hospital breast screening clinic expressed concerns about the consultant's diagnoses.