Research carried out in Oxford has suggested aspirin should not be used to prevent heart attacks and strokes - contrary to official guidance.

Aspirin is often recommended for people at risk of heart attack or stroke.

But research by the University of Oxford found the risk of harm, including stomach bleeding, largely cancelled out the benefits of taking the drug.

Study leader Prof Colin Baigent, from the clinical trial service unit, found only those who have already had a heart attack or stroke should be advised to take a daily aspirin.