Up to half the adult population should be offered cheap blood pressure pills to cut the risk of heart attacks and strokes, an Oxford University study has concluded.

Cardiologists called for an “urgent review” of NHS guidance, saying the widespread use of such drugs could save millions of lives.

Each 10mmHg drop in systolic pressure was found to reduce the risk of heart attack by one fifth, stroke by one quarter, and death from all causes by 13 per cent.

Researchers behind the Lancet study said pills should now be doled out to millions more middle-aged Britons, regardless of their current blood pressure levels.

GPs are currently advised to offer such drugs to those assessed as having high blood pressure.

Around one in four adults already meet such criteria, of whom around two thirds take medication.

But Oxford researchers said doctors should recommend the drugs to swathes of the population – regardless of their current blood pressure levels.

Instead, GPs should try to assess a patient’s overall risk of a heart attack – taking into account factors such as their age, cholesterol level, smoking habits and other health conditions such as diabetes, they said.

This could mean at least as many patients recommended for the drugs as the 17 million now eligible for statins, following controversial guidance last year, researchers suggested.

The new study analysed the findings of 123 large randomised trials involving more than 600,000 people.

Current guidance from the National Institute of Health and Care Excellence (Nice) says treatment should be offered to those with blood pressure higher than 140/90 mmHg, or 150/90mmHg among those aged 80 and over.

But the study - which examined trials with a range of blood pressure targets - found that benefits were just as great among those whose levels were far lower to start off with – including those who started off with a systolic reading of less than 130.

Overall, every 10 mmHg reduction in systolic blood pressure reduced the risks of major cardiovascular disease events and heart disease by about one fifth, and stroke and heart failure by about a quarter, and the risk of death from any cause by 13 per cent.

The research, funded through the National Institute for Health Research Oxford Biomedical Research Centre and Oxford Martin School, looked at the five main classes of blood pressure-lowering drugs, such as ace inhibitors and calcium channel blockers, all of which cost pennies. All were found to be effective.

Professor Kazem Rahimi from the George Institute for Global Health at Oxford University said: “Our findings clearly show that treating blood pressure to a lower level than currently recommended could greatly reduce the incidence of cardiovascular disease and potentially save millions of lives if the treatment was widely implemented.

“The results provide strong support for reducing systolic blood pressure to less than 130 mmHg, and blood pressure-lowering drugs should be offered to all patients at high risk of having a heart attack or stroke, whatever their reason for being at risk,” he said.

“Whether the person starts at 130 mmHg or 160 mmHg, they still got the benefit”.