Another free school has been placed into special measures by Ofsted, it was revealed today, putting further pressure on the government’s flagship education policy.

The report on The Hawthorne’s Free School in Liverpool means the percentage of free schools given Ofsted’s lowest “inadequate” rating is now nearly twice as high as the rest of the state sector, under the watchdog’s latest inspection framework

But a TES analysis of free school Ofsted reports also shows that a significantly higher percentage have been judged “outstanding”, than other state schools.

Meanwhile, it has emerged that one of the programme’s most high profile institutions, the West London Free School, has seen its second departure of a headteacher in just 16 months.

Overall, 45 Ofsted reports on free schools have so far been published, of which seven were outstanding, 23 good, ten required improvement and five inadequate.

Last month it was reported that a leaked Department for Education document showed that it wanted to tackle problems at struggling free schools before Ofsted made them public because the “political ramifications of any more free schools being judged inadequate are very high and speedy intervention is essential”.

TES compared the free-school Ofsted verdicts with overall state-school inspection judgements during 2013/14.

The analysis shows that 11 per cent of free schools were inadequate, compared to 6 per cent of all state schools. But a higher proportion of free schools - 15 per cent - were judged outstanding, compared to 9 per cent of all state schools.

Including all state schools’ latest Ofsted verdicts makes the situation look much worse for free schools, with only 3 per cent of all state schools judged inadequate and 20 per cent outstanding. But the comparison is unfair, as many of the judgements will have been made under previous, more-lenient inspection frameworks.

Inspectors found poor pupil progress and deteriorating attendance at The Hawthorne’s, a secondary that opened in 2012. “Senior leaders have an overgenerous view of the performance of the school,” they warned.

This week also saw the publication of an Ofsted report that judged another free school - Tiger Primary in Maidstone, Kent - that was deemed to “require improvement”.

Inspectors said that teachers “do not consistently set work at the right level of challenge”, but praised the school’s leadership.

TES has learned that Sam Naismith, headmaster of West Free School, had a farewell assembly at the Hammersmith secondary this week.

The school, which has just advertised for a replacement head, opened in September 2011, but saw its first head, Thomas Packer, leave his post by the end of 2012.  

Writing on the TES website today, Natalie Evans, director of the New Schools Network, a government funded charity that helps groups to open free schools, said they were “proving hugely popular”.

But she added: “A small number of free schools have - as has been very well documented - been judged to be ‘inadequate’. For a programme that was designed to drive up standards, this is not acceptable.”

A Department for Education spokesman said: “There are more than 170 free schools across the country and the vast majority are performing well. In recent weeks three free schools have been rated ‘outstanding’ and six free schools have been rated ‘good’, despite only opening 18 months ago.

“But we have demonstrated that we will not hesitate to intervene and take swift action if children are being denied the education they deserve, no matter what type of school they attend. All schools are subject to a tough Ofsted inspection framework and must meet the same high standards.”