ROKE Primary School is set to be incorporated into the Harris Federation because Riddlesdown Collegiate does not make the grade for academy sponsor status.
A letter seen by the Advertiser, from education minister Lord Nash to Croydon South MP Richard Ottaway, reveals Riddlesdown has not made the Department for Education's (DfE) "Academy sponsor pool" due to a 10 per cent drop in GCSE grades.
The letter goes on to admit that parents, teachers and the MP, who have all protested, will find it "disappointing" to know the DfE remains committed to Harris as the "best and strongest" choice.
Meanwhile, children are still "vulnerable" at Roke, in Kenley, despite an Ofsted inspection last month which found significant progress had been made since a damning report last summer.
The letter says: "We acknowledge the school is making satisfactory progress towards the removal of the Notice to Improve.
"However, whilst the school has made some improvements, the Ofsted monitoring inspection highlighted that there is still limited evidence that these are secure and sustainable, and as a result the school and its pupils remain vulnerable with a considerable amount of work still to be done.
"We have carefully considered the outcome of the monitoring visit, representations from Malcolm Farquharson (chair of governors at Roke) and yourself [Ottaway], as well as Riddlesdown Collegiate's work with Roke.
"We are also aware that some parents share your view that Riddlesdown should sponsor Roke. Having considered all the relevant factors, we maintain the view that the Harris Federation remains the best and strongest sponsor for Roke.
"We recognise that you, the school and your constituents will find this disappointing but we feel firmly this is in the best interests of the pupils at the school."
After considering Riddlesdown's results, its Ofsted rating and long-term capacity to support a school, the letter adds it was deemed not strong enough to be an academy sponsor.
Meanwhile, the Advertiser understands Harris last week visited the school to conduct a stock take as part of an assessment on how much funding they will need from the DfE to take over and run the school.
A DfE spokesman said: "The children at Roke deserve the best possible education, but any suggestion that there is a 'done deal' on a sponsor is wrong.
"Ministers will carefully consider all responses to the consultation which is due to start soon, before taking a final decision."