What would you do if someone collapsed in the street, right in front of you? Would you go to their aid? And, if so, would you know what to do? Every year in the England and Wales, up to 140,000 people die in situations where basic first aid might have saved them.
Tonight reporter Fiona Foster meets Fabrice Muamba, the now-retired Premier League footballer who suffered a cardiac arrest but survived despite the fact that his heart stopped beating for more than an hour. Fabrice is now campaigning for first aid to be taught in every secondary school.
The Tonight programme also puts the first aid skills of three members of the public to the test by reconstructing the aftermath of a multiple-injury car crash.