The US election and the Covid-19 pandemic meant 2020 was a huge year for bad info. The BBC’s disinformation experts track where the big lies came from and the harm they caused.

Bobby Friction explores filter bubbles and echo chambers on social media and we follow his attempts to break free of the filtered boundaries of his social networks.

In this edition of Archive on 4, Phil Tinline mines the archives to trace the story of 'disinformation' - navigating the slippery history of such incidents as the Zinoviev Letter, the Reichstag Fire, the Moscow Trials and the allegations that the US used germ warfare in the Korean War.

Has the internet democratised news journalism, creating a new plurality of reporting and opinion? Are we witnessing the healthy overturning of the apple cart of the entitled metropolitan elite who’ve run the media for so long? Or are the moral rules of journalism being scrapped and the old expectations of objectivity and fairness being replaced by a toxic digital fog of instant comment, rumour, cynicism and outright lies? Is this a danger to democracy or just entertaining political theatre? Are those who complain about accuracy and spin confusing facts with truth?

Tim Harford explains - and sometimes debunks - the numbers and statistics used in political debate, the news and everyday life.

Angela Saini investigates the lethal spread of alternative facts and discovers that the very architecture of the web amplifies dangerous pseudoscience online.

The Culture Select Committee’s final report into fake news and disinformation has heavily criticised the practices of tech firms like Facebook. Amol Rajan discusses its findings with Labour MP and member of the the Select Committee, Ian Lucas, Dex Torricke-Barton, former executive at both Google and Facebook and Stephen Lepitak, Editor of the tech and marketing website The Drum.

Amol Rajan discusses conspiracy theories and rogue data science with Jill Lepore and Richard Evans.