Exclusive: Anger over new £45m free school that may be be Britain's most expensive

The cost of setting up the Harris Westminster Sixth Form for high-achieving students is six times the average cost of establishing a free school and equates to around £90,000 per pupil.

The decision comes months after the National Audit Office questioned the Government’s controversial free schools programme and accused the Department for Education of failing to exert control over its rising capital costs.

The Independent understands that the budget for this project – which is being sponsored by Westminster School – has been the subject of internal criticism within Whitehall.

Senior officials have privately questioned the value for money of the school which aims to send half of its pupils to Oxford or Cambridge and will prioritise children who are on subsidised school meals or who come from deprived areas, provided they first pass its selection test. The school said that of the 167 children offered places for its opening in September 61 per cent met those criteria.

But Margaret Hodge, chair of the Public Accounts Committee, described the expenditure as “outrageous”.

“This is nothing more than a vanity project that is taking precious resources away from areas which really need it in a time of austerity,” she said. Her own Barking constituency is “desperate for good quality school places for our children”, yet Mr Gove’s plans would only serve “a tiny number of pupils”, she said. “I’m all for helping children from disadvantaged backgrounds … but why does this school have to be in one of the most expensive areas of London?”

Today’s revelation comes just a month after The Independent revealed that existing state sixth-form colleges had suffered more than £100m in budget cuts over the past three years – forcing some to abandon A-level options such as maths and languages.

At the same time, there is expected to be a shortage of 240,000 primary school places by 2015 and pressure on places is acute in London.

So far the Government has spent £743m on establishing 174 free schools for 80,000 pupils. Capital costs of securing premises have been almost double DfE predictions.

Christine Blower, general secretary of the National Union of Teachers, said:  “When sixth-form budgets are being cut to the bone, this is an outrageous waste of money. The Government’s free school programme is clearly in complete disarray.  These vanity projects coming in at such huge expense to the taxpayer and benefiting only a few need to be stopped.”

The shadow Education Secretary, Tristram Hunt, added: “David Cameron’s Government has displayed a shocking degree of complacency in responding to the need for new school places – at a time when we are at crisis point for primary places.

“National Audit Office data show that, overall, two-thirds of all places created by the free schools programme – Cameron’s flagship schools policy – are being diverted away from areas of high and severe need for primary places. When times are tough, it is right that the first priority should be addressing basic need – that would be Labour’s priority.”

It is understood that the £45m cost was subject to a “significant difference of opinion” within the DfE where critics say that by concentrating large resources on the brightest children at a time when budgets are constrained means other children might miss out.

“At the end of the day it was Michael Gove’s decision,” said a source. “And no one could stop it.”

But a spokeswoman for the DfE robustly defended the plans tonight. “This is an inspirational collaboration between the country’s top academy chain and one of the best private schools in the country,” she said. “It will give hundreds of children from low income families across London the kind of top quality sixth-form previously reserved for the better off.”