COMPLAINTS about treatment by doctors outside normal working hours have risen significantly over the past seven years.
The Medical Defence Union, which provides legal, ethical and complaints handling for more than half the UK's doctors, said complaints about GPs working out of hours were relatively small, but increasing.
A survey by Helen Goodwin, the MDU's clinical risk manager, revealed they account for 10% of all complaints made to the union.
In 1997, it was just 1%.
The picture is similar in Huddersfield.
Dr John Clarke, chairman of Pendoc, the service which was formed in 1999 and provides out-of-hours GP coverage for half the doctors in central Huddersfield and 75% of those in the Holme, Colne and Dearne valleys, said: "There is possibly a slight increase in the complaints we now receive.
"We used to get one patient complaint every two weeks.
"We now get one to two a week.
"However, we now cover twice as many doctors than when we started, which is roughly 200 GPs - and we are covering them for longer periods."
Most GPs work from 7am to 6.30pm, Monday to Friday.
Cover outside those times is provided by services such as Pendoc.
"In terms of hours we are doing a lot more than we were," added Dr Clarke.
He believed that clinical error did not happen more than before.
But patients were now more familiar with complaining than they used to.
"We are probably making it easier for people to complain, which is what we want them to do," said Dr Clarke.
"It is surprising what can be learned from complaints."
The MDU says that from 1997 to the end of last month, 421 complaints arose from out of hours care.
Twenty-one were made in 1997, as against 120 last year.
Already this year there have been 116 complaints.
Dr Karen Dalby, also a clinical risk manager for the MDU, said: "The rising number of complaints about out-of-hours care is perhaps surprising, given the relatively small number of these consultations that take place, compared to those during surgery hours.
"We do not know for sure why patients are complaining more about out of hours treatment.
"But it could be because of the change in the way these services are provided.
"Over the last few year, more GPs have been switching to out- of-hours co-operatives - a group of GPs coming together to provide out-of-hours care in shifts - or deputising services."
Dr Dalby said this could mean a patient is not seen by their regular doctor.
The deputising doctor will also not have access to medical records.