“Let me throw a hypothetical operation onto the table,” the article continues. “The Islamic State has billions of dollars in the bank, so they call on their wilāyah in Pakistan to purchase a nuclear device through weapons dealers with links to corrupt officials in the region.”

It admits that such a scenario is “far-fetched” but warns: “It’s the sum of all fears for Western intelligence agencies and it’s infinitely more possible today than it was just one year ago.

“And if not a nuke, what about a few thousand tons of ammonium nitrate explosive? That’s easy enough to make.”

An attack launched by Isis against America would ridicule “the attacks of the past”.