Schools minister Nick Gibb has written the letter he promised to the Commons Education Committee about the size of a multi-million-pound pupil premium funding gap – but has told MPs the amount is still unknown.
Mr Gibb was asked by the committee last month to reveal how much money will be saved by changing the way pupil premium funding is allocated this year.
Five weeks later, the committee had still yet to receive the evidence.
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Mr Gibb has now provided a response addressing the question, but has failed to quantify the savings.
The schools minister said that the data from the January census was still being collected, so the government could not say how much it was set to save from the change at this stage.
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This is despite the fact that the official return date for the spring census was almost five weeks ago, on 17 February.
The letter states: "We will confirm pupil premium allocations for the financial year 2021-22 in June 2021. Overall, pupil premium funding is expected to increase to over £2.5 billion in 2021-22 as more children have become eligible for free school meals
"Data on the number of pupils who have become eligible for free school meals since 2 October 2020 – which is necessary to calculate any financial implications associated with the move from the January to October census – is being collected as part of the spring school census and is not yet available. This is particularly uncertain in 2021 in the context of Covid.
"The department publishes information annually from the January school census on the number of children eligible for free school meals and the number who claim a meal on school census day. The figures form part of the 'Schools, Pupils and their Characteristics' release and are usually published in June."
The June publication date will be long past the point at which pupil premium funding begins to be allocated according to the change, from April.
Announced quietly before Christmas, the policy shift means the government will calculate the number of children attracting pupil premium funding from April based on a census from last October, and not in January, as schools had been expecting.
Children who became eligible for free school meals between October and January will therefore not attract pupil premium money in school budgets allocated from April this year.
Pressure has been growing on the government to change tack. Last week, England's new children's commissioner, Dame Rachel de Souza, indicated she thought the policy was wrong.