The MI5 head identified Russia and China as countries presenting a state-based threat to Britain. McCallum described Moscow as delivering "bursts of bad weather," while Beijing as "changing the climate".
"On state-backed hostile activity, I think we are looking at two lines that are going to cross," Mr McCallum said in his first public comments as director general of the Security Service. If the question is - which countries' intelligence services cause the most aggravation to the UK in October 2020 the answer is Russia," he said, speaking at the Home Office in London,” McCallum said.
He then added that China will be shaping “our world across the next decade, presenting big opportunities and big challenges for the UK.”
The MI5 chief also commented on threat from terrorism and right-wing extremism.
"In April of this year MI5 and our police colleagues completed the phased transition we had begun in 2017; against this sadly rising threat, MI5 now holds lead intelligence responsibility. We operate entirely the same system as on Islamist extremist terrorism, with cases pursued by the same counter-terrorist professionals within the same part of the MI5/police machine, operating to the same thresholds, prioritised on the basis of threat and risk rather than ideology. This threat is not, today, on the same scale as Islamist extremist terrorism. But it is growing," he said.
McCallum has been named the new head of Britain's MI5 intelligence agency in 2020. He has worked at MI5 for 25 years, oversaw counter-terrorism probes in the lead-up to the 2012 London Olympics.