The headteacher tasked by the government with improving social mobility has said she “feels sorry” for independent schools, which she feels could be teaching their pupils “so much more”.

Katharine Birbalsingh, who leads Michaela Community School in North London and is sometimes dubbed Britain’s “strictest headteacher”, was recently appointed as chairwoman of the government’s Social Mobility Commission.

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In a conversation with the charity Now Teach’s co-founder Lucy Kellaway, Ms Birbalsingh said: “I look at private schools and feel rather sorry for them.”

She added: “They could be pushing children so much more and teaching them so much more.

“These children have to rely on their parents to hire tutors for them because they’re not being taught properly in their lessons.”

Ms Birbalsingh said that she did not see private schools as having a creative ethos, stating: “I see it as being stunted.”

“They end up with 7s, 8s and 9s because the schools aren’t doing that great a job,” she added.

Ms Birbalsingh is known for her strident views, particularly on behaviour, and has previously criticised independent schools with “progressive” approaches to teaching.

On her appointment in October, she said her  immediate priorities included “developing a sound evidence base from which change can flow...so that we really can ‘level up’ every region of the UK.”

A spokesperson for the Headmasters’ and Headmistresses’ Conference group of independent schools said: “We welcome Katharine Birbalsingh to her post as Social Mobility Commissioner and look forward to working constructively with her to improve outcomes for all children in this country.

“100 per cent of HMC schools work in collaboration with local state schools on academic, pastoral, cultural and sporting partnerships and we don’t accept the picture Ms Birbalsingh describes.”