Michael Gove has been accused of suppressing figures about a possible increase in food prices after Brexit.
The government has refused to publish a Department for Environment, Food and Rural Affairs (Defra) analysis because “premature disclosure of information could seriously mislead the public and is not in the public interest”.
Unite, the union which represents food, drink and agriculture workers, submitted a Freedom of Information (FOI) request to the department.
It asked: “What assessment or estimate has been made of the increase in food prices in the run up to the UK leaving the European Union and the first five years after the UK’s departure.”
However in a response seen by HuffPost UK, Gove’s department turned down the request.
“We recognise that there is a public interest in disclosure of information concerning the increase in food prices in the run up to the UK leaving the European Union and the first five years after the UK’s departure,” Defra said.
“However, there is a strong public interest in withholding the information, in this instance.”
Gove was one of the leading figures in the Leave campaign during the referendum.
Defra said there was a “strong public interest in withholding the information” as it could “seriously mislead” people.
The department said civil servants also need “a safe space” to “formulate policy effectively”.
Unite national officer for food, drink and agriculture, Julia Long said: “The government is pulling the wool over the eyes of the public yet again. What are they hiding?
“If the government knows that Brexit is going to affect food prices, then they need to tell the general public and not pretend that there isn’t a problem.
“The type of Brexit that the UK chooses will clearly have major implications on the nations shopping basket and we need to know what those factors will be.
She added: “Unite will do everything it can to ensure that this report is published and will hope that other individuals and organisations with similar concerns will also apply pressure for this information to see the light of day.”
Tom Brake, the Lib Dem Brexit spokesperson, said Gove should “show a bit of honesty”.
“Brexit Britain is not going to be the land of milk and honey that he dreamed of,” he said.
“The truth is clear that on our current path prices will go up, jobs will be lost, public services will suffer and Britain’s place in the world will be diminished.
“This government are dragging the country disastrously and reckless out of the EU. The British public must have a say on the final deal. The Liberal Democrats are the only party offering the people an exit from Brexit.”
This week the food industry warned food prices could increase if the UK crashes out of the EU without a trade deal.
However former Tory environment secretary Owen Paterson, who campaigned for Brexit, said families could actually get a ”£300 plus annual bonus” by removing tariffs from food after the UK leaves the EU.
In its response to the FOI, Defra said: “The information requested is being withheld as it falls under the exemption in section 35 of the FOIA, which relates to the formulation and development of government policy.
“In applying this exemption, we have had to balance the public interest in withholding the information against the public interest in disclosure.
“We recognise that there is a public interest in disclosure of information concerning the increase in food prices in the run up to the UK leaving the European Union and the first five years after the UK’s departure.
“However, there is a strong public interest in withholding the information, in this instance.”
“At this early stage of the policy process, where the UK is formulating its negotiating position with the EU, a public authority needs a safe space to formulate policy effectively and to ensure the information it is preparing is timely and accurate.
“Defra’s EU Exit policy development work is ongoing. We consider that premature disclosure of information could seriously mislead the public and is not in the public interest. In the meantime, however, Defra will continue to monitor food prices.
“Therefore, we have concluded that, in all the circumstances of the case, the information should be withheld.”