Image caption Schools must become academies by 2020 or have official plans to do so by 2022, says the government

Labour is predicting the government's plan to convert all England's state schools to academies could cost more than £1.3bn.

The party says the figure is based on a Parliamentary written answer which shows the government paid £66,000 per school for earlier academy conversions.

This would leave a black hole of more than a billion pounds in the education budget, Labour says.

The government says suggestions of a shortfall are "completely untrue".

Under the plan, announced by Chancellor George Osborne in his Budget last month, all state schools must become academies by 2020 or have plans to do so by 2022.

It would mean every English school being funded directly by central government rather than through a local authority.

Conversion costs

Labour's new calculations rely on an answer from children's minister Edward Timpson, to a question on how much the Department for Education had spent on academy conversions.

The answer shows the DfE spent £323m converting 4,897 schools to academies between April 2010 and January 2016.

Labour says this gives a figure of just under £66,000 for each conversion.

Multiplied by the total number of schools to convert - 16,800, including special schools and pupil referral units - Labour says the total cost of the programme to the DfE will be £1.1bn.

On top of this, separate figures highlighted by Labour suggest the legal costs to local authorities could amount to £206m, bringing the overall cost to over £1.3bn.

Last month's Budget allocated £640m over four years to be split between meeting the cost of full academisation and of a new formula to end uneven levels of funding for schools in England.

But Labour says the Budget document earmarks a total of £500m for the new national funding formula.

If this comes out of the £640m that would leave just £140m for academisation, Labour maintains.

This would leave a shortfall of more than £1.1bn given the government's own figures for conversion, says the party.

Money allocated

The Conservatives have called Labour's figures "shoddy", as some of the £500m for the new funding formula will come from money already allocated in the Autumn Spending Review as well as from the Budget. However, they did not specify the proportion.

Image copyright JEFF OVERS Image caption Shadow education secretary Lucy Powell called the academies plan costly and unnecessary

Shadow education secretary Lucy Powell told the BBC: "There is no school improvement argument as to why this reorganisation is necessary.

"It is a costly, bureaucratic reorganisation which is an ideologically-driven process.

"It is not about school improvement and it's not, either, about autonomy for schools. If it was about autonomy for schools, then schools could - as they can now - choose to become an academy if that's what they so wish to do.

"This is about forcing upon all schools in the country a costly reorganisation which, when they are facing budget cuts over the next few years as they are... I think this money could be much better spent on improving standards in schools and on extra teachers and on extra-curricular activities."

In a statement, a DfE spokesman did not address the detail of Labour's calculations but said: "It is completely untrue to suggest there will be a shortfall of funding for our academisation plans.

"As set out in the Spending Review, and in last month's Budget, we have enough funding to support a high quality, fully academised school system.

"We have over £500m available in this Parliament to build capacity in the system, including recruiting excellent sponsors and encouraging the development of strong multi-academy trusts."