Patients' groups expressed horror at the "sick experiment" in which NHS managers have agreed to pay £38 for every casualty that ambulance staff "keep out of Accident and Emergency" (A&E) departments after a 999 call has been made.
The tactic is part of an attempt to manage increasing demand for emergency care amid failings in the GP out-of-hours system.
Documents seen by The Sunday Telegraph disclose that staff at Britain's largest ambulance service have been encouraged to maximise the organisation's income, by securing payments for diverting patients to telephone helplines.
The bonuses are among dozens of schemes being tried out by ambulance trusts across the country as they attempt to improve their emergency response times and help A&E departments meet controversial targets to treat all patients within four hours of arrival.
Another plan uncovered would see thousands of 999 calls currently classed as urgent downgraded so that callers receive telephone advice instead of an ambulance response.
The changes were due to be introduced across the country this week, but the Government committee governing ambulances has delayed its decision amid safety concerns.
Last week, an investigation was launched at the ambulance trust piloting the scheme following the death on Thursday of a man whose case was referred for telephone advice when an ambulance should have been immediately dispatched.