England, Wales ban water cannon use by police. How do UK police tactics compare globally?

Home secretary Theresa May is worried about medical risks the water cannon may cause, especially 'without safeguards' to regulate its use.

The British Home Secretary has prohibited the use of water cannon as a means of crowd control in England and Wales, according to the BBC.

Water cannons are used in Northern Ireland, but have never been used in the rest of the UK, the BBC reports.

Most recently, law enforcement officials deployed water cannons to “patrol sectarian flashpoints at the climax of Northern Ireland’s marching season” on Monday, according to The Guardian.

London Mayor Boris Johnson, who is said to be unhappy with the ban, had authorized £218,000 for the purchase of three water cannons a year ago, according to The Guardian.

Home secretary Theresa May, who initiated the ban, told the BBC that, while the use of water cannons was "unlikely to result in serious or life-threatening injuries", there were still "direct and indirect medical risks," including spinal fracture, concussion, eye injury and blunt trauma.

A statement by the Met Police defended the potential use of water cannons, saying: "We believed allowing police the option of deploying water cannon, even though they would be seldom seen and rarely, if ever, used, was a sensible precaution which would allow us to deal with a number of specific public disorder situations more safely and effectively than we are currently able."

Britain actually has a very limited track record when it comes to fatal police incidents.

In 2014, the British police force killed one person – a man who was threatening a woman with a knife, according to The Guardian. This was the first time police shot someone to death since 2011.

This is in stark contrast with the United States.

According to citizen-run database Killed by Police, which provides links to media reports for each death, US law enforcement officers have killed 620 people so far in 2015. Last year they killed just over 1,100.

A 2014 investigation by The Wall Street Journal found that hundreds of police killings in the US aren’t even counted in federal statistics.

When it comes to non-lethal police weapons, some countries have gone beyond tear gas and rubber bullets.

India, for instance, became the first nation to use weaponized drones for crowd control in April. The machines are “used to shower pepper powder on an unruly mob,” says Yashasvi Yadav, chief of police in the northern Indian city of Lucknow, where the drones have been tested.

Most countries permit the use of non-lethal weapons for crowd control, but ban their use in warfare, as delineated by international law – the 1925 Geneva Gas Protocol and the 1993 Chemical Weapons Convention, according to the International Committee of the Red Cross.

A 2015 report by the American Civil Liberties Union analyzed the potential dangers that can come allowing American law enforcement to use what are called “less lethal” weapons.

They recommended the US “apply rigorous government standards for the design and use of such weapons, which would include an assessment of the risk of death and serious injury, specific training required, and what contexts police can use them in.

Home Secretary May said "without safeguards," water cannon had "the capacity to cause harm," according to the BBC.