Hundreds of jobs are under threat at health advice service NHS Direct under plans which unions warned would lead to the closure of 24 sites.
Unison said it was "truly shocked" at the announcement, which it believed would lead to hundreds of staff being made redundant. The union said 24 out of 30 sites in England would close at the service, which employs 1,500 front-line nursing and other professional staff.
NHS Direct denied that any decisions had been taken to close centres. It added that centres in Carlisle, Dudley, Exeter, Milton Keynes and Middlebrook, Bolton, would be used to provide the NHS 111 service, which is used in cases where a patient needs medical help, but it is not a 999 emergency.
One of three sites in Greater London will also be used, but it has not been confirmed whether it will be the site in Beckenham, the Ilford office, or the centre at NHS Direct's head office in Leman Street, east London.
The future of the following sites are uncertain: Chesterfield, Derby, Hull, Mansfield, Newcastle, Nottingham, Sheffield, Stockton, Wakefield, Blackburn, Kendal, Liverpool, Nantwich, Stafford, Bedford, Chatham, Chelmsford, Southampton, Ipswich, Norwich, Bristol, Ferndown in Dorset, and Truro.
Nick Chapman, NHS Direct chief executive, said: "Unison's fears that 50% of front-line staff will lose their jobs are also unfounded.
"The Department of Health has agreed that NHS Direct's front-line staff will be offered the opportunity to move into a job providing the new 111 service with other providers (ambulance trusts and GP out-of-hours organisations) where NHS Direct is not the chosen provider of the 111 service in an area.
"The future of other NHS Direct sites has not been decided. We are in discussion with the Department of Health and the NHS Commissioning Board about the future of other non-111 services that we could be asked to deliver before making decisions."
Unison said a firm announcement should be made about the future of the service to allay its job warnings. Sandra Maxwell, Unison's convener at NHS Direct, said: "Hundreds of dedicated nursing and NHS professionals are to be made redundant at a huge cost, when their skills could be used within the new NHS 111 service, if only the Department of Health took some decisive action.
"Given that many of these NHS call centres are in areas of high unemployment there are very real fears for the staff's future job prospects. The Government spending millions on making nurses and NHS professionals redundant at a time when the NHS is under great strain is truly scandalous."