The researchers looked at stroke incidence across the UK

The Stroke Association said 50,000 strokes a year - 40% of the total - could be prevented if people took steps to keep their blood pressure under control.

This can be done by regular monitoring coupled with taking exercise, switching to a healthy diet, and, if still necessary, medication.

Main symptoms of a stroke sudden numbness or paralysis drooping muscles sudden slurred speech difficulty finding words

Around ten million people in the UK have high blood pressure, and many of these are among the 130,000 who have a stroke for the first time each year.

However, a survey carried out by the charity has found that 84% of people are unaware of the risks.

Six out ten of the 999 people questioned did not know, even roughly, what their blood pressure was.

The survey also found:

• 62% of people knew someone close to them who had had a stroke
• Of those 40% had died because of the stroke
• Over a quarter - 28% - were unable to list any of the main symptoms of a stroke

Dr John Pittard, a GP from Middlesex, said: "Patients should ask their GP or practice nurse for more information on reducing their risk of stroke and ensure they have their blood pressure checked regularly so that it can be adequately controlled if necessary."

A stroke is the term used to describe the effects of an interruption of the blood supply to an area of the brain causing brain cells to be damaged or to die.

It is the biggest cause of disability in the UK. Of those who suffer from a stroke, only one in three go on to make a full recovery.

It is estimated that the annual cost of stroke to the NHS is over �2.3 billion.

The Stroke Association is launching a campaign to raise public awareness of stroke.