Worried Facebook-users who have deleted their accounts because of the Cambridge Analytica scandal have been discovering that the social network held even more data about them than they had feared: complete records of their phone calls and text messages, contacts from their address books, appointments from their calendars, reminders of their friends' birthdays... It is naïve to suggest that we can ever again be truly private individuals, however much we might like to be, but is the harvesting of our personal information getting out of hand? The moral issue is not just about privacy - whether these companies should have such information about us in the first place - but is also about the ways in which it can be used. Is it right to divide up the population into sub-groups, without their knowledge, so they can be precisely targeted with advertisements and political propaganda? "Shocking!" say some newspaper pundits. "It's what advertisers and campaigners have always done," say others. What, if anything, should be done about it? Harsher punishments? Stricter regulation? Is it the moral duty of companies to be more transparent, beyond the small-print 'Terms and Conditions' that hardly anyone reads or understands? Cheerleaders for Big Data point to its potential to transform our lives, improving health and education. Its detractors say the abuse of personal information is nothing less than a threat to democracy. And there are some who believe both positions are overstated and who worry that we have lost faith in the public's ability to make its own judgments. Witnesses are Silkie Carlo, Christopher Graham, Timandra Harkness and Katz Kiely.

Producer: Dan Tierney.