The Holocaust never happened. The planet isn’t warming. Vaccines cause autism. All of us deny inconvenient truths sometimes, but what happens when denial becomes ‘denialism’, a systematic attempt to overturn established scholarly findings? And how do we relate to this phenomenon in a ‘post-truth’ age? Our panellists, whose expertise covers history, contemporary culture, the law and psychotherapy, discuss the significance of phenomena such as Holocaust denial and climate change denial, and how they relate to ‘everyday’ denial.