If general practice fails the whole NHS fails, experts have warned as they highlighted the bleak financial pressures facing family doctors.
Martin Roland, professor of health services research at the University of Cambridge, and Sir Sam Everington, chair of Tower Hamlets clinical commissioning group, said that "urgent action is needed" to tackle the crisis in general practice.
In a new editorial published in The BMJ, the pair argue that the vast majority of patients are seen by GPs but increases in funding tend to move more toward hospitals.
The share of NHS money that goes to general practice has fallen from 11% in 2006 to under 8.5%, they said.
"General practice has been described as the jewel in the NHS crown," they wrote.
"GPs currently manage the great majority of patients without referral or admission to hospital. If the current strain on general practice were to shift this balance only slightly, hospitals would be overwhelmed."
They added: "Politicians and NHS leaders argue that more care should be moved into primary care, but increases in funding move inexorably into hospitals."
General practice needs "fair funding" to deliver on the plans, they said.
"Urgent action is needed to restore the NHS. But the crisis will not be averted by focusing on hospitals. If general practice fails, the whole NHS fails," they wrote.
The pair said that there needs to be a "substantial injection" of new funding into general practice.
There also needs to be more support for GPs to free them up from mountains of paper work and performing tasks that could be done by less qualified staff.
Prof Roland added: "GPs need to feel valued rather than continually criticised by politicians and regulators.
"Many practices are at breaking point, with an increasing number simply handing in their contracts and closing."
A Department of Health spokeswoman said: "General practice is the bedrock of the NHS. We recognise that it is under pressure which is why we are seeking to reduce burdens upon it and deliver record investment, with funding for the sector increasing by around 4-5% every year for the rest of the Parliament.
"We have committed to having 5,000 more doctors in general practice by 2020 and the Health Secretary will shortly announce further support for GPs, which should assist in meeting the pressures doctors are reporting."