Statins don't harm the memory – and could even prevent cognitive decline in those with heart disease or high risk of dementia.

The findings follow a long debate about possible side effects of the daily pills, taken by around 8 million adults in the UK to prevent heart attacks and strokes.

The six-year study of more than 1,000 people aged 70 to 90, who underwent a battery of tests and brain scans, found no link between statins and memory impairment.

And the Australian research, published in the Journal of the American College of Cardiology, found that certain groups saw improvements in cognitive skills, after taking the drugs.

On one recall test, those with heart disease taking statins saw a boost of up to 13 per cent, while those with genes which increase the risk of Alzheimer’s disease saw performance improve by 16 per cent.

Lead researcher Professor Katherine Samaras, head of the clinical obesity, nutrition and adipose biology lab at the Garvan Institute, Australia, said: "We carried out the most comprehensive analysis of cognition in elderly statin users to date, and found no results to support that cholesterol-lowering statins cause memory impairment."

"What we've come away with from this study is a reassurance for consumers to feel more confident about their statin prescription."