An “overwhelming proportion” of pupils at one of the country’s largest academy chains are not receiving a good enough education, according to a damning judgement by Ofsted, which also cast doubts over the sponsor’s use of pupil premium funds.

The watchdog has released its findings from the inspection of 16 E-Act academies, which it visited following concerns over standards. The support offered to the schools by the E-Act is “ineffective”, inspectors said.

The report is the latest bad news to hit the provider. Earlier this year, the Department for Education (DfE) revealed that it had been forced to take control of 10 of the chain’s schools due to failing standards.

E-Act has also been investigated by the DfE amid concerns around financial mismanagement. The probe subsequently led to the resignation of E-Act’s then-managing director Sir Bruce Liddington.

In a letter published today, Ofsted said that it had completed inspections of 16 academies in the chain over a two-week period in February: five of these institutions were judged to be failing and put in special measures; a further six were told they “require improvement”.

Inspectors also found that 10 of the schools had made no improvement since their previous inspection, of which six had actually seen their standards drop. Two of these had been sponsored by E-Act for four years or more.

Senior staff also raised concerns with inspectors that not all of the pupil premium funding that the schools were receiving was being used to support disadvantaged children.

The letter states: “During the inspections, senior staff informed inspectors that E-Act had, until 1 September 2013, deducted a proportion of the pupil premium funding from each academy. It is unclear how these deducted funds were being used to improve outcomes for disadvantaged pupils.”

In addition, the letter said the inspections highlighted a range of key weaknesses such as poor quality teaching, weak monitoring and use of performance data as well as weak governance.

Mike Cladingbowl, Ofsted’s national director of schools, said E-Act had “not been effective” in improving its academies.

“Ofsted is determined to shine a light wherever we have concerns about the quality of education and, where necessary, we will continue to monitor the individual schools within the Trust to ensure progress is being made,” he said.

The release of the judgements comes just days after it was revealed the DfE has a list of 14 academy sponsors that are banned from expanding.

In a statement, E-Act’s chief executive David Moran said Ofsted’s verdict had confirmed that standards in some of its schools were “not acceptable”.

“No-one should be in any doubt about E-Act’s commitment to the task of improvement. That commitment is driven by E-Act’s mission to break the link between poverty and underachievement,” Mr Moran said.

“The 24 academies that are remaining with E-Act will be fully engaged with all that we have to offer. A commitment to high standards is worth something only when matched by the will to deliver high standards, and ultimately when those standards become the norm. That’s exactly how E-Act is approaching this new phase.”

In a separate letter to the chain, schools minister Lord Nash said Ofsted’s findings were “hugely disappointing”, adding that ministers were “extremely concerned” about the number of E-Act academies that are not yet “good”.

The Conservative peer added that he intends to issue “pre-warning notices” to three more schools under the chain’s control due to poor Ofsted judgments. The minister has already sent out two such notices to E-Act academies. 

“I cannot stress enough the seriousness of the position E-Act is currently in or the willingness of the Secretary of State to take further, robust action if improvements are not made,” Lord Nash said.