Video game loot boxes have been blamed for a "deeply concerning" rise in the number of children with a gambling problem.
According to an audit by the Gambling Commission, the number of problem gamblers aged between 11 and 16 has reached 55,000, with a further 70,000 at risk and 450,000 children said to bet regularly.
The findings noted that close to a million young people had been exposed through loot boxes in video games.
So, what are they?
Loot boxes are a stash of mystery in-game items, tempting players with the possibility that any of the crates they buy could contain something of huge value.
In the case of football game FIFA 19, they are trading card-style packets that can be bought with either real money or a digital currency earned by playing.
According to Eurogamer, the most expensive "gold" pack costs about £1.20 in real money but only gives a 4.5% chance of securing one of the best players in the game.
How did they emerge?
Publishers and developers have long been searching for ways to tempt players to spend extra money on their games.
In recent years, some of the biggest titles have gravitated towards tempting purchases dubbed "microtransactions" that can quickly add up to huge revenues.
According to TechSpot, publisher Activision Blizzard raked in more than half of its record $7.16bn annual revenue last year from in-game purchases in shooter games such as Call of Duty and Overwatch.
When did they become a problem?
One of the most egregious recent examples of games with loot boxes was Star Wars: Battlefront II – an online shooter timed to the release of Star Wars: The Last Jedi last year.
Before it hit store shelves, fans found out that the only way they could unlock new weapons and abilities was to buy loot boxes – not knowing exactly what they would end up with.
This approach was condemned as "pay to win" and led to publisher EA turning off the ability to spend money in-game.
Has any action been taken?
Loot boxes have been banned in Belgium and the Netherlands as they are deemed to be gambling.
In April, the Belgian Gaming Commission found that FIFA 18 and Overwatch were among those in violation of gambling laws and were therefore illegal if their loot boxes were not removed.
Belgian justice minister Koen Geens said at the time: "It is often children who come into contact with such systems and we cannot allow that."
More from UK
In August it was announced that video game boxes across Europe would soon sport an icon warning parents of the potential for extra purchases.
Last October, the UK government said it was "monitoring convergence between gambling and video games closely" after a petition calling for gambling laws to include games marketed at children hit 10,000 signatures.