The deputy chief medical officer, Professor Aidan Halligan, is to quit his job to take over as head of the Irish health service.
Professor Halligan, who was born in Ireland, studied at Trinity College Dublin and did his initial medical training in the city. He will take up the new post in April.
He described the move as "a fantastic once-in-a-lifetime opportunity for me", saying: "To be head of the Irish health service will be an honour and an exciting chance for me to return to my roots."
He added: "I have learned a great deal over the last 10 years in the NHS, and I'm looking forward to using that experience to give something back. Until I take up the position in April 2005, it will be business as usual for me here in England."
Prof Halligan, who was appointed deputy CMO last year, is also the NHS's director of clinical governance and until 2002 headed the clinical governance support team based at the NHS Modernisation Agency.
He has also been head of obstetrics and gynaecology at Leicester Royal infirmary trust and professor of fetal maternal medicine at the University of Leicester.
Throughout his rise through the Department of Health hierarchy, Prof Halligan has kept a direct involvement in clinical practice, maintaining a regular cloinical session at Guy's and St Thomas' trust.
The chief medical officer, Sir Liam Donaldson, said: "Aidan has made a very positive contribution to our work, in particular in developing clinical governance and improving the quality of care. His leadership in the transformation to modernise medical training and more recently helping to lead the national programme for IT will also leave a positive legacy. We are sorry to be losing Aidan so soon but I wish him well in his new post."
The NHS chief executive, Sir Nigel Crisp, said: "Everyone here at the Department of Health wishes Aidan the very best of luck in his new role in Ireland. Aidan has made a tremendous contribution in a number of policy areas. He is widely respected throughout the NHS and I'm sure his expertise and wisdom will be missed by many of us. Ireland's gain is our loss."
