Campaigners have blasted a decision by the government to block the release of information on ministerial discussions about new grammar schools.

The Department for Education (DfE) has rejected a Freedom of Information request by KentOnline, arguing disclosure is not in the public interest and could have a corrosive impact on policy-making.

But activists say people have a right to know what is being discussed in government regarding such a controversial issue.

It comes after Liz Truss, during her brief spell as Prime Minister, instructed the then secretary of state Kit Malthouse to examine how new grammars could be created.

It would have potentially ended a ban introduced by Labour when it came to power in 1997.

Ms Truss had committed to consider the case for re-introducing selection during the leadership campaign, saying that she wanted more children to have the option of attending a grammar school. Her two daughters attended grammars.

But while education officials did produce some options and there were ministerial discussions on what could be done, the DfE says disclosure of the details is not in the public interest.

It has rejected KentOnline’s Freedom of Information request for reports, briefing notes and ministerial exchanges related to new grammars.

The request was refused by the DfE through the application of a Section 36 exemption that said disclosure would be prejudicial to the conduct of public affairs.

The refusal notice said: “It is in the public interest that the formulation of government policy and government decision making can proceed in the self-contained space needed to ensure that it is done well.

“Good government depends on good decision making and this needs to be based on the best advice available and a full consideration of the options.

“Without protecting the thinking space and the ability for ministers to receive free and frank advice, there is likely to be a corrosive effect on the conduct of good government, with a risk that decision making will become poorer and will be recorded inadequately.

“It is the Department's view that the public interest in non-disclosure outweighs the public interest in disclosure in this case.

“Disclosure of the withheld information would be likely to have a potentially corrosive effect on good government and lead to less fully-informed decision making. This is not in the public interest.”

Campaigners against selective schools said the government should be more transparent. Joanna Bartley, of Comprehensive Future, said: “It's disappointing that the DfE won't share information on the decision making around new grammar schools.

“The public deserves the right to know what is going on with school policy, and this policy is a controversial one that needs full transparency.”

The Department for Education did publish a list of academic papers, research, reports and data which indicated that it was concerned about the issue of social mobility and a new generation of grammars.

Ms Bartley added: “The academic papers that were shared as the research base for the DfE show overwhelming evidence that grammar schools admit woefully low number of disadvantaged pupils.”

While Rishi Sunak also committed to examining ways in which selection could be introduced during the campaign, it emerged last December that he was abandoning the idea and the current ban on new grammars would remain in place.