Speaking of the Mafia’s skillful financial management, as detailed by The Economist seven years ago, the BBC’s new study on jihadist groups muses on the crucial nature of funding.

This has always been known, as it quotes Cicero’s wise observation that “the sinews of war [are] a limitless supply of money.”

The BBC writes that “Skilful financial management is at the heart of the success of any terrorist or insurgent organisation – it represents their lifeblood but is also one of their most significant vulnerabilities.”

But as with the Mafia, starving Islamist extremists of money is not easy. Crime pays for violence. It always has.