The Government’s reforms to Ofsted risk being a “step backwards” in terms of schools’ improvement, the Conservative shadow education secretary has warned.

Changes announced by the new Government mean that schools will no longer be issued with one of four headline grades for overall effectiveness – outstanding, good, requires improvement and inadequate – when inspected.

This academic year, parents will still be able to see the four grades across the existing sub-categories: quality of education, behaviour and attitudes, personal development, and leadership and management.

From early 2025, the Government will also introduce regional improvement teams that will work with struggling schools to address areas of weakness.

In cases of the most serious concern, the Government will continue to intervene, including by issuing an academy order, which may in some cases mean transferring to new management.

Shadow education minister Damian Hinds told the Commons that between 2010 and 2024, the proportion of schools rated less than good came down from around one in three to one in 10.

He said: “I worry these changes mean less transparency for parents and a step backwards from a proven school improvement approach with academy trusts to a directive top-down approach, and I urge the Secretary of State and her minister to assess the true impact this will have on young people’s prospects before it’s too late.”

Mr Hinds also argued that the Government had not “thought through the consequences” of the changes and the overall effectiveness assessment is “a vital indicator for parents”.

Education minister Catherine McKinnell said Labour is “a party of high and rising standards for all of our children in all of our schools” and that reform to inspection was “urgent”.

She continued: “Inspection and accountability are crucial tools for achieving better outcomes for all of our children.

“We will take no lessons from a party under whose watch one in four children left primary school not having met the standards expected in maths and in reading, and where one in five children are persistently absent from school. It’s not good enough and we are determined to fix it.”

Liberal Democrat education spokeswoman Munira Wilson said Ofsted should be a “helpful friend” to schools.

She told the Commons: “I personally have witnessed first-hand how teachers and teachers in my constituency have suffered under the strain and stress of Ofsted inspections, but others have also told me how helpful they found them and how brilliant Ofsted inspectors have been.”

She added: “So whilst this is a welcome first step, could we have some reassurances that this will be followed by proper root and branch reform? For too long, Ofsted has been seen as an adversary and it should be seen as a helpful friend.”

Ms McKinnell said the inspecting body is “determined to change” and the Government will work with it to deliver the changes required.

Former education secretary Sir Gavin Williamson asked what “the trigger mechanism” for intervention in schools would be under the new inspection system.

Ms McKinnell responded: “Where the Government currently has a legal duty to do so we will continue to intervene, but we will also look to put that improvement support through our regional improvement teams in place for schools that are struggling as well, because no child should be left in a school that is letting them down.”

Conservative MP Sir Julian Lewis suggested a numerical rating system that would not be subject to “subjectivity and relativism”.

He said: “Could not the simplistic one-word system that is now being replaced be replaced by a proper marking system where individual aspects of a school are specifically marked and an overall figure given? Which would therefore be not subjective but would give parents an easy guide as to the performance of the school.”

Ms McKinnell said the Government’s consultation would look at a range of options on delivering their aim of providing “greater transparency, greater clarity, greater information for parents and for schools”.