The number of complaints about NHS hospitals and community health services in England is at a record high, figures showed today.
The sector has also seen the biggest annual rise in complaints since records began 12 years ago, according to data from the NHS Information Centre.
Between 2008/09 and 2009/10, the number of complaints rose from 89,139 to 101,077 - a 13.4% rise and the biggest year-on-year increase since 1997/98.
The data refers to the number of written complaints about NHS hospital and community services.
Previously, the biggest yearly rise was 10.6% between 1999/2000 and 2000/01. Since 1997/98, there has been an average annual increase of 1.1%.
Today's report showed that, in 2009/10, the highest number of complaints (44.2%, or 44,682) related to the medical profession, a similar proportion to the previous year.
The second highest proportion related to nurses, midwives and health visitors (22%, or 22,203), while NHS trust administrative staff accounted for 9%, or 8,635.
When broken down by topic, the biggest percentage of complaints related to "all aspects of clinical treatment" (42.2%, or 42,727 complaints), followed by staff attitude (12.2%, or 12,331), and delays or cancellations to outpatient appointments (10.6%, or 10,710).
All NHS trusts and community services are required to supply data for the report but it is not compulsory for foundation trusts to do so.
There are 130 foundation trusts, of which 18 did not supply any data for the study.
Separate figures showed a 4.4% rise in annual complaints about GP services and dentistry, to reach 50,755 in 2009/10.
NHS Information Centre chief executive Tim Straughan said: "This report shows the biggest annual rise in written complaints about NHS hospitals and community services for 12 years.
"However it is important to bear in mind that there has been a substantial increase in NHS activity in England over time.
"For example, information from two of our other data collections show that hospital admissions increased by 28% between 1998/99 and 2008/09, while GP consultations increased by an estimated 44% between 1998 and 2008."
Health Minister Paul Burstow said: "These figures mark the last 12 months of the Labour Government's stewardship of the NHS.
"Despite the hard work of NHS staff, they demonstrate that, after 13 years of targets and tickboxes, more people than ever complained about their experience of the NHS.
"The biggest annual rise in complaints in 12 years is the public's verdict of the last Government's NHS record.
"The coalition Government is determined to put patients at the centre of everything the NHS does.
"Quality and outcomes will be the measures by which the service is judged."
Katherine Murphy, chief executive of the Patients Association, said: "The rise in complaints is very worrying and is reflected in an increase in the number of people contacting our helpline to tell us of problems they are having with NHS services.
"These figures can be quite dry, and I would urge people to think about what kind of things people complain about.
On our helpline we hear absolutely appalling stories of neglect, misdiagnosis and a distinct lack of care and compassion.
"We know many people receive good care but that doesn't excuse the poor care received by others. Keep in mind many people want to complain but don't and these figures will certainly massively underestimate the number of people that actually want to complain.
"The rise might actually reflect greater awareness of the complaints process."
She added: "It is absolutely outrageous that 18 foundation trusts did not participate in the report.
"The local communities of those trusts deserve to know how their services compare.
"At a time when the new Health Secretary is urging the NHS to become more open and transparent, it is completely unacceptable for these 18 trusts to be acting in a way completely contrary to that ethos. They should be forced to share their data."
Dr Paul Flynn, deputy chairman of the BMA's consultants committee, said: "Complaints should be seen by NHS organisations as a valuable resource, as they help them improve quality of care.
"The new system has allowed more patients to express dissatisfaction with services and we anticipate that consultants - who have overall responsibility for patients' care - will listen to this feedback and use it to work to drive forward improvements."
The 101,077 figure for complaints is the highest recorded for the NHS, according to the NHS Information Centre.
Frances Blunden, senior policy manager at the NHS Confederation, said: "When patients or their family are not happy with the levels of care they receive it is important that the process of complaining does not create further concerns.
"It is important that staff make every effort to learn from when things go wrong and NHS trusts deal with patients' concerns promptly, effectively and appropriately. This is an important part of offering high quality, safe healthcare."