The study, published in the journal Circulation, highlights the need for such drugs - called statins - to be made readily available to patients.

Experts say that in the UK, many patients are either not getting statins fast enough - or not getting them at all.

Despite clear recommendations..many health professionals remain uncertain about the ideal time that people should be receiving statin therapy

Spokesman, British Heart Foundation

Other studies have already demonstrated that cholesterol-lowering drugs could save the NHS millions each year by preventing strokes and heart attacks.

The latest study of more than 3,000 patients, carried out in California, suggests that if the statins are given early, then the benefits could be greater.

Some patients who have suffered a heart attack, or even just chest pain, go on to have a stroke just months afterwards.

Half the 3,000 patients were given a statin within four days of hospitalisation - the others a harmless "placebo".

Half the risk

Out of the 3,000 patients, 36 had strokes.

However, while 12 of these were on statins, 24 of them were taking the "placebo" tablets.

Professor David Waters, chief of the division of cardiology at San Francisco General Hospital, said that the findings were significant.

He said: "An estimated 1m to 2m people a year suffer from acute coronary syndromes each year in the US alone.

"If these results are confirmed in future studies, an absolute reduction of stroke of this order means that many strokes would be prevented."

Stroke all-clear

The study also seems to put to rest fears that taking statins could increase the risk of a different kind of stroke - a haemorrhagic stroke, which involves a burst blood vessel on the brain.

There were only three haemorrhagic strokes - all in the "placebo" group.

A spokesman for the British Heart Foundation said there was little doubt that statins worked - so it was time to give them to as many suitable patients as possible.

She said: "Statins have been found conclusively to reduce mortality and morbidity.

"Despite clear recommendations set out by the National Service Framework (NSF) in 2000 many health professionals remain uncertain about the ideal time that people should be receiving statin therapy.

"The BHF will soon be producing a patient's guide to the NSF which will allow patients and health professionals to have a better understanding of when statins should be taken."