A head whose school finishes at the wrong end of ministers' new spending tables because of an accounting anomaly says their drive for transparency is ill thought out and "extremely misleading".
From this week, detailed information on exactly how every state school in the country spends its budget was made available to anyone with a computer.
Ministers have trumpeted the spending tables as a "new era of data transparency" - an "educational equivalent" of the Go Compare consumer finance website that will allow parents to see whether schools are delivering value for money.
But a TES analysis of the new statistics has demonstrated how they can give the wrong impression. They say that Perry Common Junior and Infant School in Birmingham spent a whopping #163;4,168 per pupil on back-office administration - a total of #163;816,999, nearly twice as much as the #163;2,630 per pupil the school spent on teachers.
The published figure for back-office spending is easily the highest for a primary in the country, more than 47 times the national median per pupil average of #163;298. But the figure has been inflated because it includes hundreds of thousands of pounds the school agreed to hold for a local education action zone, an on-site private daycare centre and a local extended schools scheme.
"We will have put these down as back-office expenditure because there is nowhere to put them," said headteacher Jo Jones. "The system doesn't allow it. But this is extremely misleading because this is not the school's money. It couldn't have been spent on pupils."
Removing the extra funds reveals the school has spent just #163;435 per pupil on back-office administration, well below the Birmingham median average.
"Parents do need access to information but it has got to be accurate," Mrs Jones said. "This should have been more carefully thought through."
Teaching unions had already warned that the information would encourage simplistic comparisons.
The tables show exactly how much money each school has received and break spending down into 12 categories, including teachers, support staff, energy and catering. They allow quick comparisons with exam results and average national and local authority school spending in the same category.
"They will know for the first time whether the school down the road is doing twice as well with much less money," a Department for Education spokesman said.
Education secretary Michael Gove insisted the aim was "not to point fingers". "We need to ensure that every pound is spent as effectively as possible and the best way of doing that is by shining a light on the best practice," he said.