The number of patients seeking private treatment is likely to rise in response to lengthy waiting lists and postcode lotteries, doctors have claimed.
A report published by Doctors for Reform has accused the government of failing to face up to the reality that healthcare in the UK is no longer "free at the point of delivery".
"Patients are beginning to develop sophisticated approaches to purchase upgrades to their basic NHS care," the report claims.
The report also includes 20 case studies of patients who chose to pay for private treatment because the NHS provision was insufficient or unavailable to them, ranging from private maternity services through to heart disease and cancer treatment.
The doctors have sent their report to politicians and are calling for a debate into the future of funding for healthcare.
One of the UK's health insurance providers, WPA, has highlighted the lack of access to treatment by announcing a new policy which will underwrite the cost of cancer drugs not available on the NHS, according to the Guardian.
For less than £100 a year, consumers will benefit from the knowledge that they will have access to life-prolonging drugs which would otherwise prove unaffordable.
Independent advice on private healthcare