Around two in every five GPs in one region of England are planning to quit – exposing a potential doctors' crisis in the NHS.
A survey of more than 2,000 GPs in the South West of England exposed the region's impending healthcare catastrophe.
Figures published last month show there has been a drop in the number of GPs working in the NHS despite Government aims to recruit 5,000 more by 2020.
The survey, which was carried out by the University of Exeter, also found that seven out of 10 GPs intend to change their working patterns in a way that would mean less contact with patients.
This included leaving patient care, taking a career break, or reducing their hours.
The researchers said the data provided a snapshot of low morale which, if echoed in other regions, could point to a deeper and more imminent crisis than previously anticipated in relation to the worsening shortage of GPs nationwide.
Professor John Campbell, who led the research, has called for a move away from "sticking plaster solutions" towards robust, joined-up action to avert the crisis nationwide.
"We carried out this survey because of a nationally recognised crisis in the shortage of GPs across the country, and our findings show an even bleaker outlook than expected for GP cover, even in an area which is often considered desirable, and which has many rural communities," Prof Campbell, a practising GP, said.
"If GPs have similar intentions to leave or reduce their hours in other regions, as many are reporting, the country needs to take robust action more swiftly and urgently than previously thought."
The research team sent surveys to 3,370 GPs across the region and received responses from 2,248, with 54% reporting low morale.
Prof Campbell said: "We know that there's an ageing workforce in general practice, with 30% of GPs being over 50 years old.
"Previous research has found that GP morale is low because of workload pressures, and many younger GPs do not want the financial risk and responsibilities of taking on a practice.
"Yet if the GPs we surveyed fulfil their intentions to leave or to cut back their patient contact, and no action is taken to address the issue, the South West of England will experience a severe shortfall of GPs in the next five years.
"Whilst numerous Government-led initiatives are under way to address recruitment, there is a need to address the underlying serious malaise which is behind this data.
"We are in a perilous situation in England, with poor morale of the current GP workforce, and major difficulties with recruitment and retention of GPs reflected in the stark overall reduction in the GP workforce. Reactive, sticking-plaster approaches are not the answer."
Prof Campbell said GPs and their teams deliver nine out of every 10 patient contacts with the NHS but attract just seven pence in every pound of NHS spending.
"The Government needs to work with the Royal College of General Practitioners, the British Medical Association, and universities to obtain evidence on the causes of the problem, to develop and implement relevant strategy, and to effect fundamental change in healthcare resourcing and planning nationwide," he said.
:: The paper, Quitting patient care and career break intentions among general practitioners in South West England: findings of a census survey of general practitioners, is published in BMJ Open.
Dr Bruce Hughes, chairman of the Devon Local Medical Committee, which represents and supports GPs in the county, said: "The research reaffirms the significant challenges our grassroots GPs and practices face every day as they strive to deliver high-quality patient care.
"Like elsewhere in the country, local GPs are grappling with heavy workloads which have already reached a tipping point.
"There simply aren't enough GPs to deal with the anticipated further rising demand due to a lack of entrants into the profession, retirements, those choosing to leave through burnout or disillusionment, or who have reduced their hours or moved abroad for a better work-life balance.
"The situation is likely to get worse as many GPs may become overwhelmed due to the anticipated increase in demand as a knock-on effect of community hospital bed closures.
"Our problems may be exacerbated further by the recent national announcement to commit more GPs to work in A&Es."
Dr Hughes added: "The profession can no longer function on the dedication and goodwill of GPs who are already running on empty and who year after year suffer further setbacks with respect to increasing demand and bureaucracy and reductions in workforce and available resources."
Dr Krishna Kasaraneni, the BMA's GP committee lead on education, training and workforce, said: "Many GPs are voting with their feet because of the daily struggle of trying to provide enough appointments to patients without the resources or support they need.
"Given the uncertainty of whether the UK's departure from the EU will result in more overseas doctors leaving the NHS, this shortage could well get even worse in the years to come.
"With the NHS at breaking point, we need the Government to take the evidence of a workforce crisis seriously and act to implement a long-term, well-funded plan that results in more GPs being available to treat the public."
A Department of Health spokeswoman said: "This sample survey was carried out before we launched our world-leading plan to improve conditions in general practice – so it doesn't take into account our steps to improve morale and retention by investing £2.4 billion more into primary care, making extra payments to GPs, and cutting red tape while increasing flexible working.
"To ease future workforce pressures, we are also now training the highest number of GPs since records began."