Religious belief tends to be associated with lower rates of alcohol and drug use, but cannabis has been shown to increase people’s preoccupation with religion, especially in young men.

Surely, it is no coincidence that time and time again, in the aftermath of recent terrorist attacks, as we learn more about the perpetrators and try to understand their motivation, we discover that cannabis was a part of their daily lives.

Mohammed Emwazi, known as Jihadi John — the man who murdered hostages James Foley, Alan Henning and David Haines, among others — was reportedly a heavy cannabis smoker.

Richard Reid, the shoe bomber who tried to blow up a plane flying from Paris to Miami in 2001, smoked cannabis as a youngster, as did the killers of Fusilier Lee Rigby, Michael Adebolajo and Michael Adebowale.