Out-of-hours appointments have been available in parts of the country since 2014 and NHS England said all surgeries should provide the facility from October 1 this year as part of its GP Forward View.
But new figures have revealed that around half a million evening and weekend appointment slots have been left empty.
The data, from 80 of the country’s Clinical Commissioning Groups (CCGs), shows 37 per cent of Sunday appointments go unfilled, 24 per cent on Saturdays and 23 per cent on weekday evenings.
In Kent, Thanet CCG saw only three per cent of Sunday appointments being booked since April, the figures revealed.
Leading doctors have raised fears of CCGs being pressured to offer the service at a time when they lack the resources and staff to do so.
Dr Richard Vautrey, a Leeds doctor and British Medical Association (BMA) GP Committee Chairman, said: “Because it has become a political must-do, everybody is jumping. We understand there is huge pressure from the centre on CCGs to demonstrate they are providing a full seven-day service.
“Sensible CCGs that want to use their resources in a better way are under pressure to maintain a service that really isn’t good value for money.
“That is ridiculous so I think we really do need to see much more common sense and pragmatic flexibility.
“If we had the luxury of resource and workforce then we could look at extending the service but until then we’ve got to focus on what is most important.”
Figures showing the uptake of out-of-hours GP appointments were obtained by Pulse magazine, which sent freedom of information requests to CCGs. NHS England has pointed out that six out of 10 CCGs did not respond to the Pulse survey.
An NHS England spokespersons said: “Patients want quicker access to a trusted GP both during the working week and outside traditional surgery hours, and are increasingly prepared to vote with their feet to get it.
“To suggest that people should always be forced to take time off work if they need to see their GP would be backward step, and as the popularity of new types of online digital primary care shows, patients are increasingly prepared to vote with their feet to get convenient access.”
Bosses at NHS Leeds CCG confirmed that the uptake of the out-of-hours GP appointment service, which now covers the whole city population, was 75 per cent in August.
Extended GP access in the city is provided at “hubs” located in GP practices after doctors teamed up to offer the service.
An NHS Leeds CCG spokesperson said: “All registered patients in Leeds now have access to additional appointments at evenings and weekends in line with the NHS England commitment outlined in the GP Forward View.
“Patients should be able to book appointments at the hub via their registered general practice which also includes telephone and face to face appointments.
“The service in Leeds has been rolling out across the city over the past couple of months but now covers 100 per cent of the population.
“The average uptake for August 2018 was 75 per cent and provided an additional 7,000 appointments to the city.”