text: Perry Beeches III is one of a chain of six free schools. Mr Cameron described the schools as "a real success story".
  But the Ofsted report said too many students were underachieving and described teaching as "inadequate".
  Perry Beeches chief executive Liam Nolan said he "fundamentally disagreed" with the inspectors.
  The school's headteacher, Darren Foreman, its senior leadership team and chair of governors have resigned, Mr Nolan said.
  Mr Nolan has taken on the role of interim head teacher, together with Jackie Powell.
  The report said: "Teaching is inadequate. Too much is dull and fails to engage students who became bored and start to fidget."
  It also accused the school's leadership of having an, "unrealistic and inaccurate" view of the school and added students' behaviour required improvement.
  Mr Nolan said: "This judgement makes me question Ofsted's credibility."
  However he said he intended to work with Ofsted to make the school outstanding.
  He described the report as an, "unfortunate blip".
  He said: "Within six months you will see us back on the top."
  The Perry Beeches schools are funded by central government but not run by local authorities.
  Two of the other schools in the chain have been rated "outstanding" by Ofsted.
  Perry Beeches III was opened by the Prime Minister in September 2013.
  At the time, he said the majority of free schools were, "a real success story we should build on as a country".
  A Department for Education spokesman said: "Liam Nolan and the Perry Beeches free schools are transforming the life chances of children in Birmingham, in some of the most deprived communities of the country.
  "The performance of Perry Beeches I and II has set the bar for schools across the rest of the country.
  "Swift action has already been taken to change the leadership of Perry Beeches III and to turn around the performance of the school."
target: A £7m Birmingham free school opened by Prime Minister David Cameron is to go into special measures following a highly critical Ofsted report.