It is a staggering thought.
Until a fortnight ago, the NHS ambulance service did not owe the thousands of people it dealt with every day a 'duty of care'.
In other words, if the service you had been promised as a result of your 999 call failed to turn up, or came late, it was not liable if your health suffered as a result.
It may also come as a surprise that your legal status, as a 999 caller, was not that of a 'patient' in a hospital.
You may have thought that as you put the phone down you were safely under the benign auspices of the NHS; legally, however, you were in the hands of an emergency service, which is a different kettle of fish.
A Court of Appeal ruling has changed all that. Two weeks ago it upheld a High Court decision that a woman should be paid more than£360,000 in compensation after she suffered brain damage in 1991 because an ambulance failed to arrive in 'reasonable' time through the 'carelessness' of the London Ambulance Service.
It means that the ambulance service now has a legal duty to respond to all 999 calls with an effective guarantee that it will arrive in reasonable time.
The ruling has potentially weighty implications. It could lead to hundreds of fresh claims, adding millions of pounds to the medical negligence bill.
And in the week LAS chief executive Michael Honey resigned - apparently scapegoated for failing to turn the service round - the threat of more legal action could force health authorities to devote more resources to ambulance services.
The NHS Litigation Authority is considering whether to appeal to the House of Lords, but the Court of Appeal has already ruled that victim Tracy Kent should get her damages, whatever the result of any further legal action.
Already lawyers are rubbing their hands. The imposition of a duty of care on ambulance services could be lucrative, particularly if services are failing to cope - as several are - with the pressure of rising numbers of 999 calls and journeys.
Much turns on a clarification of the words of Appeal Court judge Lord Woolf. He said that a duty of care was owed to a member of the public on whose behalf a 999 call was made 'if, due to carelessness, the ambulance failed to arrive within a reasonable time'.
The carelessness clause suggests that if an ambulance service can demonstrate that it had taken all possible steps to reach the incident in time, and could satisfactorily prove it had been delayed by circumstances beyond its control, it would have a defence.
The reasonable time definition is harder to call. According to pre-hospital care experts, the optimum performance might constitute, for example, an ambulance reaching all serious life-threatening cases within eight minutes, at most. A reasonable time for a cardiac case might justifiably be argued to be eight minutes.
But, in theory, services are funded to meet a Patient's Charter target of reaching 75 per cent of serious cases within eight minutes over the course of a year. The London Ambulance Service says its HAs fund it to reach 90 per cent of calls within 14 minutes - a target which it claims to meet.
Five years ago it was only 62 per cent. But it admits that the most recent figures, for the first week of October 1999, show only 86.4 per cent of crews made it in time. And only just over 30 per cent hit the eight-minute target.
Can a service be in neglect of its duty of care if funding effectively means that it will not reach one in 10 people within 14 minutes? Or that one in four will not get an ambulance in eight minutes?
Are HAs in a position to invest the extra millions needed to hit the eightminute target every time?
Mike Willis, the chief executive of West Country Ambulance trust, says: 'If you have got the resources and you do not deploy them you are open to criticism and litigation.
'But what if all your resources are committed, or your purchasers do not give you enough resources to meet the Patient's Charter standards?'
Resourcing is a key issue, he adds. For example, the Changing Childbirth report of a few years ago recommended that paramedics should have extra training in obstetrics.
But according to Mr Willis, few HAs funded this training. 'If we got sued in an obstetrics-related case where the paramedic has not been funded to acquire those skills, where does liability lie?'
Reasonable time also varies according to geography. 'Rural times are affected by trips that might be up to 40-50 miles.
Any reasonable person could not expect the same standard of provision as you would if you were in the middle of London, or Plymouth, ' he says.
Alan Parker, acting director of the Ambulance Services Association, says there now needs to be a 'considered view' on what ambulance services will be expected to provide.
'The implications are significant because commissioners will have to purchase up to the required level.'