Heavy use of social media by children has been linked to lower levels of literacy for the first time.

The landmark study by University College London (UCL), based on 11,000 children tracked from their births in 2000, found their time on social media could be detracting from reading and homework, with a potential knock-on effect on their literacy.

Professor Yvonne Kelly, director of UCL's International Centre for Lifecourse Studies, said the findings suggested a link between “the amount of time young people spend on social media and their levels of literacy”.

Both boys and girls who were heavier users were affected the same. “We looked at whether the more time young people spend on social media, the less time they have for the things that might improve their literacy such as reading for enjoyment and doing homework,” said Professor Kelly.

She said it was now time for the government to consider setting official “healthy” time limits on children’s social media use outside school. Her research also showed heavy users of social media – and particularly girls – were more likely to be depressed.