Academies in England overspent by £280 million last year, according to the latest statistics from the Department for Education.
The total income for academies during 2015/16 was £18.93 billion, but spending for the year came to £19.21 billion.
The figures showed academies overspent by 1.5 per cent of their total income – up from 1 per cent in 2014-15.
Just under half of single academy trusts (1,014 of 2,064) were found to have spent more than their income in 2015/16, while the figures show six in ten multi academy trusts (661 of 1,081 trusts) also overspent.
However, the in-year deficit does not necessarily mean these academies or trusts are in debt, as they may have had reserve funds from which they could dip into to meet the costs.
Paul Whiteman, general secretary designate of the NAHT union said the statistics are “damning”. “Although much of this could have come from reserves, it does show that school funding levels are unsustainable.
“All schools, across all phases of education, are finding it hard to balance budgets.”
He said many schools will find it difficult unless real terms cuts are addressed. “It cannot be right that per pupil spending is going down, at a time when costs schools are facing are going up. This is storing up trouble for the years ahead.”
The report also showed half of academies expenditure (50.1 per cent) went on teaching staff, followed by 11.8 per cent on education support staff and 11.5 per cent on back office functions.
Overall, spending on teaching staff has dropped by 3.2 percentage points since data first began being collected in 2011/12, though there was a small rise between 2014/15 and 2015/16.
However, the DfE statistical release containing the data adds that “with growing school numbers and changing characteristics, care should be taken when comparing over time”.
Other smaller costs for academies in 2015/16 included 6.4 per cent on premises and 4.5 per cent on non-ICT learning resources.
Other staff costs and supply staff made up 3.0 per cent and 2.3 per cent of total expenditure respectively.
A significant 94.5 per cent of the total income came from grant funding, with the remaining amount – over £1 billion – generated by academies themselves.