Russell Hobby, the general secretary of the National Association of Head Teachers, also wants the inquiry to assess how the Department for Education approves and monitors these flagship schools.
His comments were made in response to a Yorkshire Post investigation into the Government’s handling of the case at the Kings Science Academy in Bradford.
Education Secretary Michael Gove’s department is facing major questions over its failure to ensure allegations of fraud against the secondary school were properly passed onto the police for more than five months.
Mr Hobby told the Yorkshire Post the evidence suggested the DfE had taken “a complacent attitude to serious allegations made against one of their projects, at a time when they are putting unprecedented pressure on maintained schools”.
He added: “Teaching is a profession rich in integrity and highly trusted. We shouldn’t allow this to be tarnished by rushed projects pushed through at any cost. Free schools must be held to account by the DfE with the same rigour as any other school.
“There now needs to be a full independent inquiry into exactly what has happened in the case of the Kings Science Academy and more broadly into the way in which the DfE approves and monitors its own free schools in order that the nation, as taxpayers and parents, can have confidence in the way in which free schools are held to account.”
The DfE reported Kings Science Academy to a fraud unit in April after discovering the free school had submitted fabricated invoices to claim thousands of pounds of public money. However, a mistake in the way this call was recorded by the Action Fraud unit led to it being passed onto police for information only, meaning no investigation initially took place.
The DfE published its findings about Kings last month, only after a draft report from its investigation was leaked to the media.
It issued a statement at the time saying that the matter had been passed onto police who “decided that no further action was necessary”. However, days later West Yorkshire Police announced that they would be investigating the case. Three people have since been questioned under caution.
Questions from the Yorkshire Post then revealed the Home Office were blaming an administrative error at Action Fraud for the matter being passed onto police as being for information in April meaning no investigation took place until the matter was leaked.
The Yorkshire Post also revealed that the DfE never sent in their audit report detailing the financial irregularities at the school and instead reported the matter with a phone call.
Now MPs, including Labour’s Shadow Education Minister Kevin Brennan, are asking why the full report was not submitted and why the DfE failed to realise the case had not been properly passed onto the police for five months.
In a Westminster Hall debate which was held this month, Mr Brennan demanded the release of a recording of the phonecall from when the matter was first reported by the DfE.