BRIT girls spend longer glued to computer screens than anywhere else in Europe, a damning report reveals.

Experts warn hours spent on social media, such as Facebook and Instagram, is making teens fat.

The World Health Organisation report compared the “obesity-related behaviours” for youngsters across 42 nations.

And it reveals UK kids are among the laziest.

Among teenage girls, the Scots top the league table for most screen time, with 80 per cent spending at least two hours a day on computers.

Wales comes fourth with 76 per cent, and England seventh with 75 per cent.

Girls in Armenia and Albania were least likely to spend hours idling online.

Screen time figures for boys were even higher.

Wales was second in the European “couch potato” league, with 85 per cent glued to their screens for at least two hours.

Scotland was third with 84 per cent, and England 15th with 77 per cent.

Boys in Switzerland and Portugal were the least likely to dedicate two hours a day to sitting in from of a computer.

The shocking figures were presented at the European Congress on Obesity in Porto, in Portugal.

One in three UK youngsters are too fat when they start secondary school.

Being too heavy increases the chances of type 2 diabetes, heart, liver disease and several common cancers.

Lead researcher Dr Jo Inchley, from the University of St Andrews, said social media was impacting on kids’ health.

She said: “We know there are risks, such as cyber bullying and impact on mental health, as well as things like missing out on sleep.

“Also, there are longer-term impacts on physical health from being sedentary.

“One of the main challenges is that this kind of activity (social media and computer use) is so much part of young people’s lives these days.”

She said more needs to be done to get kids moving throughout the day.

Dr Steven Mann, research director for UK Active said the findings were “alarming”.

He said: “Modern life has changed, but when teens are spending hours hunched over Facebook, Instagram and videogames, they simply aren’t getting the exercise that they need.

“These alarming inactivity figures show that playtime is over before it has started for too many children, putting them at far greater risk of future conditions like heart disease, cancer and type 2 diabetes.”

And Tam Fry, from the National Obesity Forum, warned Brit teens are now “slaves to handheld devices”.

The WHO warns four in five fat teens will continue to struggle with their weight throughout life.

The report also shows less than half of UK youngsters consume fruit or veg daily.