LONG-TERM vacancies for doctors, nurses and midwives are growing amid "unprecedented" demand on the NHS, medical leaders have warned.

In Shetland, a third of all hospital consultant posts were empty at the end of March this year, while in Dumfries and Galloway one in five consultant posts were vacant - all of them for six months or more.

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The highest shortages continued to be among radiologists, who play a key role in diagnosing cancer.

The Herald previously revealed that NHS Scotland had spent nearly £4 million sending X-rays, CT and MRI scans to private imaging firms in the UK and abroad, including to India and Australia, amid a lack of radiologists to cope with the growing workload as more patients in Scotland are referred for cancer checks.

Dr Grant Baxter, chair of the Standing Scottish Committee of the Royal College of Radiologists (RCR), warned that the vacancies meant cancers were going undiagnosed and patients were waiting too long to start treatment.

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The latest figures from ISD Scotland, the Scottish Government's health statistics agency, show that there were around 422 consultant vacancies in total in NHS Scotland at the end of March this year, of which 254 had been unfilled for six months or more - a 24 per cent increase year-on-year.

It compares to 41 long-term consultant vacancies in March 2013.

In clinical radiology, the vacancy rate is still running at around 14 per cent - down from a peak of 16 per cent - while the proportion of general psychiatry posts lying empty has increased to nearly 12 per cent, a record high.

Simon Barker, chair of BMA Scotland’s consultants' committee, said: “Every post in the NHS that lies empty makes it more difficult to deliver high quality care to patients and adds to the pressure facing staff left covering the gap created by the vacancy.

“Demands on the NHS are already at unprecedented levels and the struggles it is facing are only made worse by not having the medical staff in place that the NHS knows is required."

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Long-term vacancies among nurses and midwives - classed as posts empty for three months or more - are also up 27 per cent year-on-year.

ISD Scotland's report also noted that while total staffing levels for NHS Scotland rose by 0.3 per cent - the sixth consecutive year where employee numbers increased - "the rate of growth is slowing" as the number of people leaving or retiring closes in on the numbers joining.

Theresa Fyffe, director of the Royal College of Nursing (RCN) Scotland, said: “In spite of more nursing staff being in post, the vacancy rate remains unchanged and number of long-term vacancy is up significantly on last year.

"The bottom line is that Scotland does not have the nursing staff it needs to care for everyone who requires it in a safe and effective way."

Sickness absence rates are running at 5.4 per cent - close to the peak of 5.6 per cent in 2006/7 - although spending on agency nurses and locum doctors is down in favour of increased use of NHS 'bank' staff.

Health Secretary Shona Robison stressed that Scotland's overall vacancy rate for nursing and midwifery - at 4.5 per cent - is much better than the 10.2 per cent rate in England and that NHS Scotland's workforce is at record levels.

She added: “To help meet the demands the NHS faces we’re putting record investment into our health service and legislating to ensure we have the right staff with the right skills in the right place.

“Spending on agency staff fell by seven per cent over the last year and we have been clear with boards that they should only use of agency as a last resort when temporary staff are required."