The Great Replacement is an idea fueling far-right recruitment around the world - the idea that white communities and culture are being purposely replaced by non-white migrants.
Many far-right terrorists have referenced this theory as the driving force behind their murderous actions - but where does this idea originate from, and how seriously should we be taking its proliferation here in the UK?
Terrorism expert Raffaello Pantucci explores the roots of the Great Replacement and asks if this is just a far-right conspiracy theory as some critics claim, or is there a kernel of truth reflected in the UK's changing demography?
If so, how are communities - and the government - managing this change? Immigration is often a difficult topic of public debate, with many people concerned that any questioning of immigration policy will label them as racist.
But if we can’t talk more openly, without fear of judgement, are we at risk of handing control of the immigration narrative to extremists?
Reporter: Raffaello Pantucci, Senior Fellow at the Royal United Service Institute, Senior Fellow at the S. Rajaratnam School of International Studies in Singapore Producer: Jim Frank Editor: Richard Fenton-Smith