Kent county council has activated no-deal plans to keep its roads, hospitals and schools open, as the government considers pulling the trigger on national contingency measures involving 30 central departments and 5,000 staff.

With the country placed on a knife-edge by Theresa May’s latest Brexit crisis, the government is preparing for “any outcome” with a decision on Monday on whether to roll out the national Operation Yellowhammer contingencies for food, medicine and banking.

Some measures have already swung into place, including Operation Fennel’s traffic management in Kent.

The Europe minister, Alan Duncan, has also said the Foreign Office staff deployed to its Brexit “nerve centre” are working to help UK citizens in the EU in the event they get caught up in a Brexit mess.

The Department of Health was due to activate emergency supply chain operations, with instructions to medicines suppliers to book space on ferries to ensure they are not caught up in queues from next weekend in the event of no-deal.

They are just two of the 12 Operation Yellowhammer areas of risk the government has planned for in the event of a crash-out, according to a National Audit Office report [pdf]. It will decide next Monday if they should all become operational, enacting no-deal plans in 30 central government departments and 42 local councils, two devolved governments and in Northern Ireland.

About £1.5bn has been allocated to Brexit planning, with three departments getting an extra £25m for Operational Yellowhammer.

It emerged on Wednesday that ministers had banned NHS hospitals from publishing risk assessments about how Brexit might affect them, allegedly because doing so could “put public wellbeing at risk”.

The Department of Health and Social Care has written to NHS trusts in England telling them not to put into the public domain their own analyses of the pitfalls facing them.

The department’s “advice” stops trusts from outlining how Britain’s departure from the EU might affect their non-clinical goods and services and staff from EU nations.

The move appears to be an attempt to thwart an attempt by the Health Service Journal website to obtain details of these possible impacts.

The HSJ disclosed on Wednesday that the DHSC has circulated guidance to trusts about how to respond to any request from it under freedom of information laws for sight of their risk assessment documents, telling them they must “not share this information”.

Meanwhile, Kent is going full steam ahead with its contingency plans to prevent gridlock on its roads in the event of congestion in Dover or Calais.

Concrete barriers have already been erected on the main port artery in Kent, with a section of the London-bound M20 between junction 8 and junction 9 now operating as a 50mph contraflow for normal traffic. Work on signage will be completed over the weekend.

The coastbound section will be closed off to all but lorry traffic from next week to allow Highways England to carry out a live daily trial to cope with possible chaos after 11pm on 29 March.

A full meeting of Kent county council will be held at 10am on Thursday to discuss Brexit preparedness, including a checklist received from the local government secretary, James Brokenshire, of issues relating to transport, supply chains, statutory services and regulatory services.

Last year the council warned it might have to deal with 10,000 lorries parked or queuing on its roads with a knock-on impact on schools, hospitals, rubbish collections and morgues.

The council has already conducted three live tests for its contingency, code-named Exercise Pale Fox, with Operation Fennel for traffic management going into action based on assumptions of six months of disruption, according to an agenda for the council meeting.

Manston airport near Ramsgate is in the final stages of preparation for use as a lorry park for up to 6,000 heavy goods vehicles in the event of gridlock.

Councillors will also hear from adult social care and health officers who have plans to minimise the risk of disruption to admissions of patients to hospitals, residential care homes and the supply of fuel, medication, cleaning and sanitation products.

Schools have also been issued with Brexit guidelines warning them to think twice before closing down in the event that staff cannot make it through the gridlock.

Extra trading standards officials have been hired for a new ports team in Dover “as a result of the predicted increase in referrals” once EU standards are no longer guaranteed in imports.

The council is also on standby in the event that “high-risk animal feed is landed” from outside the EU but transported through the bloc to Dover.

According to reports, the Brexit secretary, Stephen Barclay, told cabinet ministers in a letter: “Operation Yellowhammer command and control structures will be enacted fully on 25 March unless a new exit date has been agreed between the UK and the EU.”

Earlier this year, the chief executive of the civil service said the government would never be fully prepared for Brexit as he revealed plans to move up to 5,000 staff into an emergency command and control centre in the event of no deal.

A government spokesperson said: “As a responsible government we have been planning and continue to prepare for all eventualities and that includes managing the impacts of a no deal Brexit as they arise.”