Pre-school and primary school children are missing out on "vital" playtime in the classroom, an academic has warned.
Games complement the curriculum, a study finds
Professor Pat Broadhead of Northumbria University found the amount of time left for games had been cut by changes to the curriculum in England.
Working towards tests at age seven had had a "knock-on" effect on reception classes and pre-school groups.
The study of schools in Leeds, Sheffield and York said play helped problem-solving and social skills.
'A sense of independence'
She said: "During the last eight years or so, the emphasis on training early-years teachers has changed. This is having an impact in the classroom.
"Play-based learning gives children a sense of independence. It's a chance to explore and investigate the world.
"Children also determine the ways in which they work and use their experiences to solve problems."
Prof Broadhead said activities such as sandpit games, playing with model figures and using building blocks, had been ignored because of growing emphasis on literacy and numeracy targets.
She added: "Play contributes to all aspects of development. I hope it regains its prominence in future.
"All the changes in primary schools have pushed back the amount of play for the younger children.
"If they are allowed to play, children can participate in building the curriculum themselves."
Prof Broadhead said the national curriculum had given teachers a "fear of non-coverage" of certain areas.
This pressure had led to a barrowing of classroom activities.
Prof Broadhead said: "We need more flexibility. The more experienced early-years teachers realise the value of play. The government should do the same."