You've probably seen the clip by now of Senator Lidia Thorpe being thrown to the ground by police outside Parliament House in Canberra. 

She was trying to confront a British anti-trans-rights campaigner, Kelly-Jay Keen-Minshull, known online as 'Posie Parker', whose tour of Australia this week has attracted support from neo-Nazis, including at a rally in Melbourne. 

It's raising concerns about the growth of extremist groups in Australia. 

So what's fuelling it? 

Today, we speak with an expert on conspiracies and the far-right. 

Featured: 

Dr Kaz Ross, independent researcher