It started with one woman’s act of defiance – removing her headscarf – hijab – on one of the busiest streets in Tehran, capital of the Islamic Republic of Iran. It was an image that captured the attention of the world.  Who was this woman? And was she alone in her defiance of the mullahs?

Livvy Haydock explores the dark world of witness intimidation and finds a sophisticated and highly effective system of menacing violence amplified and driven by social media.

Given exclusive access to the far right activist who blew the whistle on the plot of preparing to murder an MP, this dispatches penetrates the secretive world of Britain’s new Neo-Nazis .