The leader of Britain's 120,000 doctors warned ministers yesterday that they had only two years to save the NHS from catastrophe.

James Johnson, chairman of the British Medical Association, said the overwhelming majority in the profession rejected the proposals for charging patients that were sent to Tony Blair on Monday by the pressure group, Doctors for Reform.

"Most of us believe in an NHS free at the point of use. If we want that to continue, we probably have about two years to get the service right," he said.

Despite five years of record growth in the NHS budget, the service in England was "in a bit of a mess". Growth had been 7% a year in real terms, but this would slow to 3% a year or less in two years. "If we can't break even on 7%, how are we going to manage on 2.5% or 3%?"

Mr Johnson said the solution was to reduce the unit costs of treatment by allowing doctors to increase the throughput of patients. This required a change in the system of payment by results that was introduced this month. "If we can't get this change of behaviour pretty soon, we are probably going to see the end of the NHS as we know it."

Chris Ham, professor of health policy and management at the University of Birmingham, told a BMA conference that trusts with big deficits will have to consider closing hundreds of beds, or even hospitals. Surrey and Sussex Healthcare NHS trust announced plans to save £20.9m a year with 400 jobs lost.

The Department of Health said the BMA was wrong to suggest the NHS is in crisis. "The NHS has just had one of its best years ever, tackling waiting times and improving the quality of services."