Some medical practices are being forced to close after failing to recruit GPs as the number of vacancies soar to 12.2%, research suggests.
The survey was carried out amongst 860 GPs and found that the average time taken to recruit a GP partner has risen from 6.6 months to 7.4 in the last year.
The research, carried out by the GP news magazine Pulse, found that 18% of GPs said they had to give up recruiting in the past 12 months after being unsuccessful.
While some practices are having to resort to hiring non-GPs to fill the gaps, others have closed down after failing to recruit a GP partner.
Despite a Government target to recruit 5,000 GP's by 2020 a report from the Commons Public Accounts Committee in April found there had been "no progress" in increasing the number.
MPs said more trainees needed to be recruited, while existing GPs should be encouraged to stay on.
In January doctors rejected government calls for GP surgeries to open seven days a week and accused the Government of using them as "scapegoats".
The plans to extend opening times were proposed to help relieve pressure on crisis-hot A&E departments.
Professor Helen Stokes-Lampard, chairwoman of the Royal College of GPs, said the problem is "staggering".
"In the most severe cases, not being able to recruit has forced practices to close, and this can be a devastating experience for the patients and staff affected, and the wider NHS.
"Being a GP is intellectually challenging, emotionally rewarding and incredibly varied - it should be an easy profession to recruit to.
The professor blamed a lack of resources and intense pressures on the failure to meet recruitment demands.
She said: "At present UK general practice does not have sufficient resources to deliver the care and services necessary to meet our patients' changing needs - meaning that GPs and our teams are working under intense pressures, which are simply unsustainable.
"Workload in general practice is escalating - it has increased 16% over the last seven years according to the latest research - yet investment in our service has steadily declined over the last decade and the number of GPs has not risen in step with patient demand.
"This must be addressed as a matter of urgency," she added.
An NHS England spokeswoman said: "This miniature survey of fewer than one in 10 GP practices is statistically incapable of giving an accurate national picture on GP posts, and what's more the survey response rate was even lower than last year which further invalidates any inferences about annual trends."