Extremism by Islamic State terrorists overseas is causing a fierce reaction by the UK far right, a senior Home Office adviser has warned.
The adviser, who has 27 years of experience dealing with right-wing extremists told the BBC that the government had underestimated the threat they pose to Britain.
He said that since last year, five splinter groups have been formed from existing organisations, following a more extreme and violent ideology.
The adviser, who prefers to remain anonymous, said that one group member told him he would like to see death camps for all ethnic minorities in Britain.
