The number of books read by children increased by almost a quarter last year, according to a report, as BookTok and other social media trends stimulated interest in reading for young people.

The 2023 What Kids Are Reading report, which surveyed children in the UK and Ireland, found that pupils read 27,265,657 books in the 2021-2022 academic year, 24% more than the 2020-2021 academic year.

The researchers found that social media trends such as the BookTok community on TikTok helped children engage with books such as Alice Oseman’s popular Heartstopper series.

The Wimpy Kid author Jeff Kinney and David Walliams remain the first and second most popular authors among primary school pupils, while in secondary school, Kinney was most popular, followed by Walliams and then JK Rowling.

However, the report found that, while average book difficulty rose as pupils became older, this was not in proportion to the rate at which the pupils should have been improving in reading.

Throughout secondary school, pupils were still reading books at almost the same level of difficulty as upper primary pupils, researchers found.

The study, which looked at nearly 1.3 million pupils across the UK and the Republic of Ireland, was carried out by the learning and assessment provider Renaissance and analysed by the University of Dundee’s Prof Keith Topping. Topping said: “Over this long period, we have seen a repeated decline in reading comprehension from primary to secondary pupils.

“To help tackle this, secondary pupils need to be encouraged to read books of increased difficulty, more appropriate to their age.”

The study found that the “striking slump” in difficulty at transfer to secondary school is marked in all regions, including the Republic of Ireland, and that book difficulty usually does not increase after transfer to secondary school.