The director general of MI5 said that although more directed plots from terrorist organisations take time to organise and carry out, psychological boosts for their causes could happen “overnight”.
Thirty-one “late-stage attack plots” have been foiled in Britain in the last four years, mainly from Islamist extremists. Six such plans were disrupted during the Covid-19 pandemic.
Mr McCallum said “inspired” terrorist acts were “by volume” the largest number of threats MI5, the intelligence services, and police face.
“There is no doubt that events in Afghanistan will have heartened and emboldened some of those extremists,” he said. “We need to be vigilant both for the increase in inspired terrorism and the potential regrowth of al Qaeda-style directed plots.”