(CNN) - A man convicted of spraying acid in a crowded London nightclub injuring 22 people has been sentenced to 20 years in prison, the city's Metropolitan Police said.
Arthur Collins, 25, was convicted in November of five counts of wounding with intent to do grievous bodily harm and nine counts of assault occasioning actual bodily harm.
Sixteen people suffered serious burns as a result of the incident, which police said resulted from a dance floor argument at the Mangle nightclub in the London borough of Hackney, in April.
"Collins went to the nightclub that night with a bottle of a noxious substance with the intent to use it to inflict serious harm. He indiscriminately and recklessly sprayed the substance in a crowded place, knowing full well the danger this would pose to a large number of people," said Hackney Borough commander, Detective Chief Superintendent Simon Laurence.
"This was a barbaric and cowardly act."
During his trial, Collins told the court he didn't know the bottle contained acid; he thought it was a liquid date rape drug, which he took from two men after overhearing them planning to spike a drink, the Press Association reported.
Acid attacks in London have increased dramatically in recent years, and police and lawmakers are now mulling ways to make weaponized acid, or "face melters," more difficult to obtain. Sales to minors are now banned.
Laugh and joke
Collins squirted the bottle in the face of the man with whom he was arguing, the court heard. He then indiscriminately sprayed it twice more, hitting a number of clubgoers, the report released by the Metropolitan Police said.
"Victims described seeing 'steam' rise above them and there being a chemical smell which made them choke," it says. Injuries included chemical burns to some of the victims' faces and bodies, and eye injuries in at least two cases.
The perpetrator stayed in the club for almost an hour after the attack as police and emergency services arrived to tend to victims, the report said. He was arrested at a residential address several days after the attack.
It added that Collins was captured on camera appearing to laugh and joke as distressed revelers, who had fled the venue, were desperately seeking help at various hospitals.
The maximum sentence for acid attacks is life imprisonment, and in September, a burglar who sprayed acid in the eyes of an elderly woman whose house he was robbing was jailed for a similar period.
Collins has a daughter with a British reality star, Ferne McCann, British media reports. The couple are no longer together.
Rising number of incidents
In 2016, 454 acid attacks were reported across London, up from 261 the year before, and 166 in 2014.
"Most of the products can be bought off the shelf -- so drain cleaner, oven cleaner -- there are different types of sulfuric acid you can buy, and ammonia," Hackney borough police Chief Superintendent Simon Laurence told CNN earlier this year.
Police have suggested that gang members may be switching to acid over knives and guns, as the liquid is harder to detect. "Acid throwing has been adopted by urban street gangs in a way that perhaps we haven't seen for a very long time," Laurence said.
And just like knife and gun crimes, acid attacks have become a predominantly male-on-male problem.
The attacks can disfigure their victims profoundly, leaving them with both physical and psychologically life-changing injuries.
"They know that acid can be very damaging and very destructive and they are in many ways seeking to mark their victim with an act of dominance or a mark of control, demonstrating their power and their ability to get to you at any time," Simon Harding, a criminologist from Middlesex University London says.
"They call (acid) 'torture in a bottle' and they want to be able to take their rival out of the game."
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