Private schools offer more extra-curricular activities, Mr Johnson said

The education secretary said time spent doing extra-curricular activities boosted communication and interaction.

He told the National Family and Parenting Institute that state primary education in England was being reformed to improve such skills.

It comes after he said he had helped a boy get a private school place because there were no "suitable" state schools.

Teachers' leaders suggested this showed he had a lack of faith in the state system.

'Essential skills'

Speaking to an audience of parents in London, Mr Johnson said: "One of the reasons why independent schools get such good results, apart from the level of selection and extra resources, is the time they spend with children doing sport, music and drama, building social skills, confidence and team-working.

"This helps children develop not just academic and vocational skills but social skills as well.

"These skills are vital in today's workforce, where the ability to communicate, interact and engage are essential - they are the skills which employers increasingly look for first."

The government was extending the school day in England from 8am to 6pm to allow children to attend sports and drama clubs, as well as homework groups will help develop these social skills, he said.

He added that primary schools in England were starting a scheme to help children develop the social and emotional aspects of education.

In an interview with London's Evening Standard, Mr Johnson said he had helped get a boy in his constituency get a private school place because there were no "suitable" state schools in the area.