Most people have no interest in their GP surgery opening at weekends, a survey of almost a million patients has found.
In a further blow to Prime Minister David Cameron's pledge to introduce seven-day services, new research showed that 81% of patients do not find current GP opening times inconvenient.
Just 15% said weekend opening would make it easier for them to see a doctor, while only 2% said they would be able to attend Sunday appointments.
When those patients who said they were interested in weekend opening were asked to rate their preferences, 74% preferred a Saturday opening.
The research team from the University of East Anglia (UEA) and the University of Oxford, used data from the national 2014 General Practice Patient Survey.
Surveys were sent to patients from all 8,011 practices in England, and some 881,000 people responded.
The new research comes after an official review released by NHS England of seven-day services found "very low" demand for Sunday appointments.
The independent review, published last week, found patients also snubbed appointments on Saturday afternoons, although Saturday mornings and weekday evenings proved more popular.
It examined data from 20 pilot sites across England - covering 1,100 general practices and 7.5 million patients - that have been testing seven-day services.
The new research from UEA found that if surgeries were open on weekends, certain groups would benefit but others, such as people with dementia, would not.
Writing in the British Journal of General Practice, the researchers concluded: "We found that most people did not think that weekend opening would help them, but certain groups, such as people under 75 years of age, in full-time work, and with certain long-term conditions were more likely to report that weekend opening would help.
"Weekend opening is less likely to be used by patients who are older or with health or functional problems less compatible with full-time employment, such as Alzheimer's disease or learning difficulties.
"Our findings suggest that Sunday opening, in addition to Saturday, would appear unlikely to add benefit."
Lead researcher Dr John Ford, from UEA's Norwich Medical School, said: "Some weekend opening pilots have already begun to show that there is a lack of demand on Sundays, and our findings suggest that Sunday opening, in addition to Saturday, would be unlikely to improve access.
"Another key problem is that many practices do not currently have capacity to provide weekend opening in addition to weekday services.
"This means that a reduction in weekday services would be necessary - which could actually reduce access for patients who find it easier to see their GP during the traditional working week."
Last week's official review, from independent consultancy firm Mott MacDonald, found there has been some success with pilot schemes, including better use of weekday GP time.
But it said there had been low up-take of weekend appointments compared with weekday ones, particularly on Sundays, except in a few regions.
As a result, some sites have cut their weekend appointments to just a few hours or scrapped Sundays, while others have ceased to offer any extended hours appointments.
The report said there is "general agreement" that the lack of success with weekend extended hours is not down to how services are communicated to patients, but "rather it is a result of entrenched patient behaviours".
The report said that the "average utilisation" of available appointments during normal core working hours was 94%, dropping to 75% during extended working hours.
A Department of Health spokeswoman said: "The public wants GP appointments seven days a week to suit their busy lives - and innovative GPs are already making this a reality.
"That demand is being met by nearly half a million evening and weekend appointments and patients say the service is invaluable. These pilots are also benefiting the rest of the NHS, reducing minor A&E visits by 15%."
The Department of Health said evidence showed that more than three in five people think GP surgeries should be required to offer appointments seven days a week.
It said it was recognised there was more to be done promoting Sunday appointments in general practice "but as this becomes normalised we expect this to improve".
Dr Jim O'Donnell, chair of NHS Slough clinical commissioning group (CCG), which runs weekend appointments, said: "We have over 97% patient satisfaction rates, and 94% would recommend the service to family and friends.
"We've seen a 22% fall in demands made on our out-of-hours service, and numbers from Slough attending our local A&E and of emergency admissions have now started to fall month on month."
Dr Maureen Baker, chair of the Royal College of GPs, said of the study: "This adds even more weight to the argument against routine Sunday opening for GP practices. Not only will it be of little benefit to our patients - but they themselves do not want it.
"We hope this research - hot on the heels of the independent evaluation of the first wave of the GP Access Fund, which found similar results - will quell the Government's obsession with seven-day working once and for all."
Dr Chaand Nagpaul, chair of the British Medical Association's GP committee, said: "These survey findings echo the results of NHS England's pilots for seven-day opening of GP surgeries, which showed extremely poor demand from patients for appointments on Sundays, and in many cases on Saturday afternoons.
"This has resulted in precious NHS resources being wasted on keeping near-empty practices open and staffed, and has taken GPs away from caring for patients in greatest need."