Education secretary Nicky Morgan has been accused of not keeping a handle on the government's plans to turn up to 1,000 failing schools into academies.
Under the Education and Adoption Bill, every school in England rated inadequate by Ofsted will be turned into an academy. Schools considered to be ''coasting'' also face being taken over as part of a fresh government bid to raise standards.
Today, shadow education secretary Tristram Hunt called on Ms Morgan to define the term in advance of the second reading debate on the Bill next week. Addressing the House of Commons, he said: "No parent wants their child in a failing, or indeed a coasting school.
"Ahead of the second reading of the Education and Adoption Bill, I'm sure the whole House will support any measure that is shown to raise standards in our schools. But in 2012, the National Audit Office condemned the cost of the government's last academies act because of poor ministerial planning. It looks like we are now facing a similar scenario.
"Will you take this opportunity to set out now your legal definition of what a coasting school is and what measures your department is taking to prevent another black hole in the Department for Education budget?"
Ms Morgan replied: "We intend to publish the definition of coasting schools when the Bill reaches its committee stage."
Mr Hunt continued: "You do not have a handle on your own Bill. One week before being asked to vote on this Bill, you can't explain the first words on the first page of the first clause of what a coasting school stands for.
"It is inspiring teachers, great teachers, who turn around coasting schools, but teacher vacancies in crucial subjects are soaring.
"If you can't tell the House what your Bill means, will you listen to headteachers when they tell you that the Tory teacher recruitment crisis is undermining turning around coasting schools?"
Later in the session, Ms Morgan admitted that 133 academies have been rated inadequate. Labour's Vicky Foxcroft (Lewisham, Deptford) asked the education secretary to confirm the number, claiming she had dodged the question five times in a television interview earlier this month.
The new MP added: "You have had two weeks to find the answer, so how many academies are failing and what are you doing for children who are being let down in these schools?"
Mrs Morgan replied: "The answer is 133 and, as I have already set out, this government takes swift action to turn around all failing academies. We want that same opportunity for children who are in failing local authority-maintained schools."