COMPLAINTS about the Scottish NHS have more than doubled in the past decade, as a leading patients' champion warned that lessons were not being learned.

In evidence to Holyrood’s health committee, the Scottish Public Services Ombudsman Jim Martin said the watchdog was facing a "long-term rise" in health complaints which were becoming “an increasing proportion of our workload”.

The SPSO received 599 health complaints in 2007-08, when the SNP first came to power, compared to 1,512 in 2015-16. More than three quarters of grievances last year related to faults with clinical treatment or diagnosis and around 12 per cent related to staff rudeness, breaches of confidentiality, and waiting time delays.

The SPSO acts as the “last resort” for patients or their families who feel they have “suffered injustice or hardship as a result of maladministration or service failure”, and who remain unhappy after a health board's internal complaint process has been exhausted.

Among the most recent serious cases was a disabled woman who died after delays in diagnosing a brain tumour and a man who was left with serious side effects after being sent home from hospital when doctors mistook his brain haemorrhage symptoms for drunkenness.

The watchdog also scrutinises organisations including councils, prisons, housing associations, and universities and colleges, but complaints about the NHS have risen fastest.

In the past ten years, complaints to the SPSO about councils, housing associations and the further and higher education sector have risen by 30, 72 and 123 per cent respectively compared to 178 per cent for the health service.

Dr Jean Turner, a former independent MSP and retired GP who headed the Scotland Patients Association, said the trend was "very disappointing" and pointed to a "really tired workforce".

She added: "When people are tired, they can be a bit sharp with people and they're also more likely to make mistakes. Tired labour never pays, so probably we should be learning that we need more staff.

"Patients are not in it to make money from complaining - they're in it to make things better for other people, so I find it sad that health boards have not been able to demonstrate that they're getting on top of it.

"You've got to admit that you will end up with a serious crisis if you don't deal with these issues that patients and their relatives are actually teaching you about when they go to the Ombudsman. "You should learn from your complaints so they don't happen again."

Mr Martin said the new NHS complaints process due to take effect from April 1 should mark "a significant shift of focus towards quick, responsive and non-defensive complaints handling".

He added: "It emphasises the importance of empowering all staff, especially those on the front line, to respond to and fix problems that arise while services are being delivered rather than pass complaints on to others."

The Scottish Government said the "overwhelming majority" of patients were happy with their care and total complaints to the NHS had fallen by four per cent year-on-year in 2015/16.

The rate of complaints is around five per 10,000 people treated.

A spokesman said: “Satisfaction in our health service is increasing, but we want to continue to improve and new procedures are being introduced to ensure quick and responsive complaints handling. Learning from the feedback from patients and families has been pivotal in NHS Scotland’s constant drive to improve its services, and when complaints are made its vital they are taken seriously.”