Children are spending hundreds of pounds “chasing their losses” on online video game purchases which offer unknown rewards, according to the children’s commissioner for England.

So-called “loot boxes”, in which gamers buy a random selection of items, should be classified as a form of gambling, according to Anne Longfield.

She has raised concerns that young people are being left open to exploitation by gaming companies that encourage them to spend money by preying on their need to keep up with friends and make further progress in a game.

Her comments came as she published a small-scale report which looks at the experiences of children who play online games.

Ms Longfield said: “Children have told us they worry they are gambling when they buy loot boxes, and it’s clear some children are spending hundreds of pounds chasing their losses.

“I want the Government to classify loot boxes in games like Fifa as a form of gambling.

“A maximum daily spend limit for children would also be reassuring for parents and children themselves.”

She also said: “With 93% of children in the UK playing video games, it is vital that the enjoyment they get comes with tighter rules that protect them from straying into gambling.

“Playing games online can be rewarding and exciting and help children to develop strategic skills and friendships, but they are also open to exploitation by games companies who play on their need to keep up with friends and to advance to further stages of a game by encouraging children to spend on loot boxes.”

The study, based on focus groups with 29 children, says “loot boxes” allow players to buy items that might be difficult or time-consuming to earn otherwise.

The contents of the box are typically not known until it is bought, and the player opens it.

One of the youngsters questioned, who plays Fifa, acknowledges that this can be like gambling, as gamers do not know what player they will get.

The study does say that for many children, buying these products is part of their gaming experience.

On in-game purchases in general, it says: “In many cases, children enjoy the excitement generated when their purchases are revealed.

“However, some children described feeling pressured to spend money by the way the game was set up, or by elements of social play.

“For these children, spending money has become a normalised part of gaming.”

Dr Jo Twist, chief executive of Ukie, a trade body for the UK gaming industry, said: “The report shows how important online play is to their lives and how games bring children together, spark creativity and equip them with vital skills for a digital age.

“We recognise the need to educate players, parents and carers about safe and sensible play habits and for the industry to take an appropriate role in doing so. This is why we already work hard to proactively tackle the challenges highlighted in the report directly.

“The industry already promotes healthy and balanced playing practices through our consumer information site askaboutgames.com and via lesson plans available for schools through Ukie’s Digital Schoolhouse initiative.

“We have also, as a sector, put in place extensive tools and settings on game platforms that allow parents to limit the time and money spent by children in games already.”

The report says that for many youngsters, gaming is a part of their social lives – they often play with friends, and it is a chance to learn new skills.

But it also looks at the negative aspects, with some suggestions that youngsters feel embarrassed if they cannot afford to buy new items, and that they do not feel in control of how long they spend playing.

Some of the older children questioned reported playing for three hours or more a day.

A Government spokesman said: “Video games can be enjoyed by children safely as part of a healthy lifestyle and we encourage parents to use built-in controls to set spending and time limits.

“But we are clear children must always be protected from harm and we will carefully consider the concerns raised in this report in relation to excessive or gambling-like behaviour.”