When rampaging British youths smashed windows, threw paint on statues and—quelle horreur!—terrorized Prince Charles and Camilla, Duchess of Cornwall, on their way to the theater last year, London Mayor Boris Johnson cautioned against overreaction:

“We could have water cannons,” he told the BBC. “We could have baton charges. We could have a very different kind of democracy. We could have many more broken heads of young people in Britain today. I don’t think that’s what people want to see.”

Add it to the list of ill-advised statements from the gaffe-happy mayor that, months later, he finds himself in just such a Britain.

Prime Minister David Cameron announced this week that U.K. police will now carry plastic-bullet guns, and are cleared to use water cannons. He has still not ruled out calling in the Army.

Perhaps fueled by overcompensatory zeal (Cameron remained on vacation in Tuscany for the worst of the rioting), the prime minister’s heavy-handedness has brought him into a spiraling conflict with the police over how public disorder should be handled. Senior officer Sir Hugh Orde said that water cannons work only on large and static groups, and plastic bullets are weapons of last resort that do not belong on London streets.

Until this week, Britain’s riot police had eschewed tear gas and flash bombs in favor of gentler techniques such as kettling, the faintly quaint practice of surrounding protesters by locking hands and forming a circle with no exits, and not letting anyone out until they have calmed down.

But British law enforcement conceded it must adapt tactics and equipment to combat a new enemy: the shockingly young (an 11-year-old is among the 1,600 suspected rioters arrested so far) and nimble rioters who consistently outran and outmaneuvered riot police.

This is proving to be a banner year for riot-control suppliers, who have equipped prevention officers in youth-led disturbances from Chile to Canada, Greece, and Egypt. An emerging market is concentrating on riot equipment that disorientates, mollifies, and arguably degrades, without threatening life.

The Mosquito, a device that emits a screeching sound at a pitch heard only by young people, is designed to so irritate youths that it deters them from loitering.

Age-related hearing loss prevents almost every adult over 25 from hearing the Mosquito’s 17.4-kHz pitch. Simon Morris, commercial director of Compound Security Services, the firm that produces the device, describes the sound as akin to an alarm clock going off in an upstairs bedroom. Others say it induces nausea and dizziness.

Though the Mosquito has attracted criticism from human-rights groups who claim the device demonizes the young, the company, whose American distributor is called Kids Be Gone, has already shipped 5,000 units in Britain and the same number in America and across Europe.

Morris told me that the firm is currently working with a Dutch riot-shield manufacturer to produce a riot-ready Mosquito. The Mosquito riot gear will feature eight to 10 speakers molded into the polycarbonate shield front, and blast its high-frequency sound at up to 130 decibels. The sound will not affect older police but will be incapacitating for youths near the front line.

“This will be extremely loud,” Morris says.

The shields will be on the market next summer, he says.

In the Middle East, the Israeli Defense Force has been “skunking” the borders of the Palestinian territories for years. Skunk, a noxious liquid mixture of nontoxic ingredients including baking powder and yeast, is blasted onto protesters from a water cannon. Those unfortunate enough to be sprayed by it describe vomit-inducing putridity, and videos on YouTube show its effectiveness at dispersing—or at least relocating—a crowd. However, skunk leaves the sprayed area smelling for weeks. If the IDF makes good on plans to export the product, prepare for stinky urban centers.

The StoppaRed, devised by Matthew Wilkinson of Nottingham, England, and developed in the U.S. by Mace, sprays aggressors with a sticky and ultraviolet red-marker gel from a pressurized container. Marketed as a personal-defense weapon, StoppaRed has led to numerous arrests. Wilkinson says the gel combats the “I had a run-in with a can of paint” defense. “The idea that people have been caught just because you had an idea, it’s quite nice,” says Wilkinson.

From the outset, Wilkinson envisioned the spray as a riot-control agent. He has tried unsuccessfully to interest the police in the product—“Perhaps the police were a bit complacent, and thought that large-scale disturbances were a thing of the past,” says Wilkinson—but calls from politicians this week to examine dye sprays for riot prevention may renew interest in the product.

“If you have a crowd running around, up to no good, and feeling safe as part of a mob, then suddenly you’re covered in paint, then you’re an individual again,” says Wilkinson. Plus, the gel severely curtails the prospect of blending into a crowd following a looting spree.

“People tend to notice you when you’re covered in a red, bloodlike substance,” says Wilkinson.