The chief executive of Northern Ireland's shadow Health and Social Care Authority is to leave the NHS there for a job with NHS London.

Former strategic health authority chief executive David Sissling had been brought in to help oversee a radical restructuring of Northern Ireland's health services in August 2006.

The authority had been due to be formally established in April next year. But plans to replace four health boards with the single authority and seven new local commissioning groups were put on hold in the summer by new health minister, Michael McGimpsey. He argued that the newly devolved administration should review changes proposed under direct rule.

The British Medical Association and the NHS Confederation condemned the delay. Both said they regretted Mr Sissling's departure.

NHS Confederation in Northern Ireland director Alan Gilbert said: 'We had accepted the regional authority and commissioning groups and wanted to go ahead as soon as possible.'

It had left 2,000 commissioning staff with an uncertain future, he added, and disappointed 62 health professionals and others appointed to work with the groups.

Mr McGimpsey said no new appointment would be made until new health structures were decided.

Mr Sissling will join NHS London in February 2008 as programme director for health for London, overseeing the primary care trust-led review of health services in the capital.

HSJ understands he was headhunted for the job in London. He was not available to comment.