Recently, London Mayor Boris Johnson described Jihadists as “porn driven losers” who have “low self-esteem and are unsuccessful with women.” He’s on to something important and profound.

According to Syrian doctors in a report in the British media, ISIS fighters are buying frilly underwear for their wives and sex slaves — and subjecting them to abnormal and sadistic sexual practices. They may well have learned this from pornography.

The Navy SEALs who killed Osama bin Laden found a fairly extensive stash of modern pornography in his possession.

The 9/11 jihadists visited strip clubs, paid for lap dances, and for prostitutes in their motel rooms in Boston, Las Vegas and Florida.

Anwar Al-Awlaki, the American-born imam who fled to Yemen in 2004 and was later assassinated by a US drone, ate a lot of pizza and visited a lot of prostitutes in the months after 9/11.

As a presumably “holy man,” Al-Awlaki mentored at least three of the 9/11 hijackers, the Fort Hood shooter, the would-be Times Square bomber (Faisal Shahzad) and the underwear bomber.

In the years since 9/11, police raids of terrorist cells in the United Kingdom, Italy and Spain have yielded countless images of hard-core child pornography.

Not only did jihadists use porn for pleasure, they also embedded secret coded messages into shared pornography and onto pedophile Web sites.

In 2011-2012, German police found more than 100 al Qaeda documents concerning terrorist plots embedded within a porn video hidden in suspect’s Maqsood Lodin’s underwear.

According to NSA documents made public by Edward Snowden’s leaks, countless “radicals” have called for Jihad by day but watched porn by night. One damaging piece of evidence shows a “militant” using “sexually explicit persuasive language when communicating with inexperienced young girls.”

This year’s Paris jihadists Amedy Coulibaly and Cherif Kouachi both kept child-porn photos on their laptops, which included “sickening pictures of young boys and girls involved in sexual acts with adults.”

Why does the jihadis’ porn obsession matter?

Pornography is literally what prostituted women are forced or paid to do. It is derived from the Greek porni (“prostitute”) and graphein (“to write”).

Porn is a global phenomenon, produced and consumed everywhere and increasingly by people of all ages — deforming the sexual development of young viewers. Watching it desensitizes the viewer to sexual aggression and strengthens existing beliefs that support violence toward women.

It is routinely very violent: 82 percent of the top-rated porn scenes involve physical aggression (slapping, spanking, gagging); 49 percent contain verbal aggression (name calling, insults). The perps are male, 94 percent of the targets are female.

It’s easy to imagine pornography’s empowering effect upon would-be jihadists, who may unable to afford the price of a wife or a prostitute, who are young, without normal sexual outlets and already predisposed to violence towards women — and to pedophilia.

Yet, while most of the Muslim world is profoundly sexist (and while porn is everywhere there, too), few Muslims approve of porn. Indeed, its leaders often castigate the West for exposing women in a sexually explicit way.

Consider the divide in Western Europe, revealed in a 2008 Gallup poll: 43 percent of the general French population found viewing porn “morally acceptable,” but only 16 percent of French Muslims did.

In Germany, it was 58 percent of the general public but only 18 percent of Muslims. In Britain, 35 percent of non-Muslim Brits viewed pornography as acceptable, but only 1 percent of British Muslims did.

Muslims may lie to poll takers about sex, but if they are telling the truth, the way to de-heroize bin Laden and all the other jihadis is not to call them “terrorists,” but rather to describe them as “porn hounds.”

Maybe Muslims are opposed to pornography — but jihadists are not.

Phyllis Chesler is a CUNY emerita professor of psychology and a fellow at the Middle East Forum. Her books include “Women and Madness” and “The New Anti-Semitism.”