Hospitals have been ordered not to tell the public about any damage they expect to suffer from Brexit because it would hurt “commercial interests”.

Requests for information about the impact on the supply of goods and services, and on EU staff numbers, should be refused, the department of health and social care has said.

Releasing the information could cause trusts “premature financial harm, and so possibly put public wellbeing at risk,” hospital bosses were told.

The guidance was revealed as Theresa May increased the threat of a no-deal Brexit if MPs still refuse to pass her deal, arriving at the Brussels summit – meaning hospitals would have to trigger emergency plans next week.

Unearthed by the Health Service Journal (HSJ), it goes as far as suggesting the relevant exemptions under the freedom of information act (FOIA) that could be used to block requests.

The advice was revealed after the HSJ submitted FOI requests to every trust in England, asking for their self-assessments of the impact of Brexit.

The department then issued guidance stating: “Our advice at this point is that trusts should not share this information, as we consider it to be commercially confidential.

Tariffs in the event of a no-deal Brexit Show all 15 1 /15 Tariffs in the event of a no-deal Brexit Tariffs in the event of a no-deal Brexit Pork There will be tariffs on pork in order to protect British farmers Getty Tariffs in the event of a no-deal Brexit Cheese There will be tariffs in place on some cheeses including €22.10/100kg of cheddar, €19.10/100kg of processed cheese and €18.60/100kg on some blue cheeses Getty Tariffs in the event of a no-deal Brexit Milk There will be no tariffs in place on milk Getty Tariffs in the event of a no-deal Brexit Car Parts There will be no tariffs on car parts imported from Europe PA Tariffs in the event of a no-deal Brexit Cars However finished cars will face tariffs of 10.6% Getty Tariffs in the event of a no-deal Brexit Alcoholic drinks There will be no tariffs on alcoholic drinks - except on some rums due to ingredients used in their distilling process Getty Tariffs in the event of a no-deal Brexit Beef There will be tariffs on beef in order to protect British farmers Getty Tariffs in the event of a no-deal Brexit Fish There will be no tariffs on many types of fish including cod, haddock, salmon and sea bass Getty Tariffs in the event of a no-deal Brexit Fruit and vegetables There will be no tariffs on almost all fruit and vegetables Getty Tariffs in the event of a no-deal Brexit Chocolate There will be no tariffs on chocolate or other cocoa products Getty Tariffs in the event of a no-deal Brexit Poultry There will be tariffs on poultry in order to protect British farmers Getty Tariffs in the event of a no-deal Brexit Ceramics There will be some tariffs in place on ceramis Getty Tariffs in the event of a no-deal Brexit Steel There will be no tariffs on steel Getty Tariffs in the event of a no-deal Brexit Coal There will be no tariffs on coal Getty Tariffs in the event of a no-deal Brexit Lamb/Mutton There will be tariffs on the meat of sheep in order to protect British farmers Getty

“Release of the self-assessment results could prejudice the commercial interests of the entities involved in the exercise (you should consider S43 of the FOIA).

“Also, release of details could cause health and social care institutions premature financial harm, and so possibly put public wellbeing at risk (you should consider S29 of the FOIA).

“You will note that the templates issued were marked as ‘Official Sensitive’ on the basis that the content would not be shared publicly.”

Each trust’s FOI lead should be responsible for considering which exemptions to apply and the wording of the response, according to the guidance.

Despite it being issued, several trusts chose to release their entire self-assessments. Some have also included parts of the information in their publicly-available board papers, the HSJ said.

Nevertheless, around 150 trusts either withheld the self-assessments using various FOI exemptions or did not respond to its request.

A department of health and social care spokeswoman defended the advice, saying: “Leaving the EU with a deal is the government's top priority, but as a responsible department it is right we are prepared for every eventuality.

“The self-assessment of the supply chain is a vital part of this work. In order to secure high quality information, it was important commercially sensitive information from suppliers was treated in confidence.”