An NHS service allowing people to see their doctor 24/7 via a videolink on their smartphone is being trialled.
The "GP at hand" app gives patients the opportunity to book an appointment at anytime of day or night and get a video consultation on their phone within two hours.
It is being trialled in London but could be expanded if successful.
The Royal College of General Practitioners (RCGPs) warned the service was "luring GPs away from frontline general practice".
Professor Helen Stokes-Lampard, Chair of the RCGPs, said: “Some patients will see this as a ‘golden ticket’ to get quick and easy access to a GP - and for younger, healthier commuters it could prove a solution to long waiting times for an appointment.
“Technology can achieve wonderful things when used properly, but we are really worried that schemes like this are creating a twin-track approach to NHS general practice and that patients are being ‘cherry-picked’, which could actually increase the pressures on traditional GPs based in the community.
“We understand that with increasingly long waiting times to see a GP, an online service is convenient and appealing, but older patients and those living with more complex needs want continuity of care and the security of their local practice where their GPs know them."
The technology behind the pilot has been developed by healthcare firm Babylon.
Mobasher Butt, from Babylon, told The Times: "We do everything from grocery shopping to our banking online yet when it comes to our health, it can still take weeks to see a doctor and often means taking time off work.
"With the NHS making use of this technology, we can put patients in front of a GP within minutes on their phone."
Using the app, patients will be able to review their appointment videos and see the doctor's notes at any time.
For cases that require a face-to-face appointment, this can be arranged through the app at GP surgeries taking part in the trial.