Does pressing "delete" really get rid of files?

2017 saw a number of significant cyber attacks across the globe - including on the National Health Service in the UK. One way to stay secure is to delete all personal data from old electronic devices, for example if you’re giving them away to someone else. But how confident can we be that deleting data means it has gone? With the help of Graham Rymer from Cambridge University, Izzie Clarke set out to discover what could be gleaned from an old, formatted hard drive...

Originally from the show Cybersecurity: When Crime Goes Online.