BREAKING: The head of MI5 has warned Britain’s migrant crisis is fuelling an increased terrorism threat. Sir Ken McCallum, in stark terms, explained how the failure to control the borders is becoming a national security issue. He has told reporters: "For the first time in almost five years, JTAC recently returned the UK terrorism threat level to SEVERE, meaning an attack is highly likely. “While the threat level change reflects the whole of the terrorist threat, the recent increase was driven in significant part by Extreme Right-Wing Terrorism. “This is a complex landscape, with many subcultures. "Over the last year, the most marked trend has been an increase in cases where extremists of anti-immigration and anti-Muslim grievance are tipping into terrorist intent; we’ve dealt, for example, with would-be terrorists aspiring to attack mosques and venues connected to immigration and asylum."