More than 34 million people will this year fail to get an appointment with their GP when they seek one, the Royal College of General Practitioners (RCGP) has claimed.
The college's prediction that one in ten prospective patients will fail to secure an appointment when they wish is based on analysis of the latest GP Patient Survey, which was published in December.
The RCGP said the number of people who would fail to get an GP appointment when they want one will continue to rise as Government cuts and the effects of an ageing population take hold.
GPs now see 340 million patients per year in total but t he NHS budget for general practice has been cut by £9.1 billion in real terms since 2004, the college said.
Each GP is handling 1,500 more consultations a year than in 2008.
The GP Patient Survey on which the predictions are based asked patients whether they were able to get an appointment to see or speak to someone in general practice.
The responses showed an increase in the number of patients failing to secure an appointment at all from 9% of patients, in the version of the survey published in June 2012, to 10% in the latest report - equivalent to an increase of 3.4 million patients annually.
The RCGP called on the Government to increase the proportion of the NHS budget spent on general practice from 8.5% to 11% by 2017.
RCGP chair Dr Maureen Baker said: "The unprecedented decline in funding for healthcare in the community has brought general practice to its knees.
"GPs and practice nurses want to provide high-quality care for every single patient who seeks a consultation, and over the last decade we have increased the number of patients we see each year in England by 40 million.
"However, GPs and practice nurses can't keep doing more for less and now that funding for general practice in England has slumped to just 8.5% of the NHS budget the service we provide is in crisis.
"All three political parties say they want to see more patients being treated in the community, where care can be provided to patients more economically, in their own surroundings, and yet resources are increasingly being diverted away from communities and into hospitals.
"By continually diverting resources into hospitals, we have fuelled a real and growing crisis in general practice."
She added: "If the Government and NHS England really want to give general practice the tools to provide high-quality and comprehensive care in the community, they must increase funding for the sector to 11% of the NHS budget by 2017."
Shadow health secretary Andy Burnham blamed Prime Minister David Cameron for scrapping Labour's guarantee of a GP appointment within 48 hours.
He said: "Within days of taking office, David Cameron scrapped Labour's guarantee that all patients shou ld be able to get a GP appointment within two working days.
"In December, Labour called on the Government to reverse this decision but Tory MPs voted against. It is one of the reasons why A&E departments are now under such pressure.
"Ministers have cut primary care budgets by close to a billion since the election and taken away the funding that kept surgeries open into the evening and at weekends.
"Now, almost 1,000 surgeries across England shut their doors earlier than a few years ago.
"On David Cameron's watch, it has got harder for people to get GP appointments.
"Patients call the surgery early in the morning only to be told nothing is available for days. It is unacceptable and ministers must take practical steps to make sure patients can see their GP when they need to."
The Department of Health (DH) described the RCGP's claims as "complete nonsense" based on misleading extrapolations of data.
The DH said the college was conflating the number of patients with the number of visits to a GP and that the figure of 34 million was based on 10% of survey respondents saying they could not see someone on a specific occasion, rather than over the whole year.
A spokeswoman said: "It's complete nonsense to suggest that 34 million people won't be able to get an doctor's appointment this year. Misleading extrapolations of partial data have been used to generate a sensationalist headline. The GP survey showed the vast majority of patients are satisfied with their GP and rated their experience of making an appointment as good.
"We know how hard GPs work. That is why we are freeing them from excessive box-ticking so that they can devote more time to patients. We have also provided £50 million to help innovative GPs modernise their services and stay open longer, to meet the needs of patients with busy lives."