A Cabinet Office document on the “reasonable worst case scenario”, dated July 2020, was leaked to The Sun newspaper.
A government spokeswoman said this “reflects responsible government ensuring that we are prepared for all eventualities.”
The file warns the military may be forced to drop food on the Channel Islands.
The navy could be required to prevent British fishermen from encountering illegal incursions by European fishing boats, the document adds.
There could be electricity and petrol shortages in parts of the UK if thousands of trucks get stranded in Dover, he also warns.
In addition, according to the assessment, drug shortages due to port blockades could lead to the spread of animal diseases in the countryside.
He also warns of the possibility that hospitals will be overwhelmed, if trade restrictions triggered by a no-deal Brexit combine with flooding, flu and a second wave of coronavirus.
The prospect of the bankruptcy of town halls is mentioned, as well as the possibility of deploying troops in the streets in the event of public disorder.
It is feared that the winter months will see a second wave of COVID-19[feminine[feminine UK.
The latest statistics available show that over 324,000 people have tested positive for the virus in the UK.
A total of 41,423 people have died in the UK within 28 days of testing positive for the disease.
Britain left the EU in January after 47 years of membership and is currently in an 11-month transition period, meaning it continues to follow the bloc’s rules and regulations.
This timeframe is used to negotiate a free trade agreement and set the terms of the future relationship that will govern UK-EU relations in the future.
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Both sides have said a deal needs to be reached by October to be ratified on time, but so far there has been no breakthrough.
Speaking after the last round of negotiations ended earlier this week, EU negotiator Michel Barnier said felt “as if we were going further back than forward”.
British negotiator David Frost said that while the latest negotiations in Brussels had been “useful”, there had been “little progress”.
Cabinet Minister Michael Gove said: ‘We did a lot on Brexit in January and we are working hard to make sure the UK is ready for the changes and the huge opportunities of the end of the year as we regain our politics and economic independence for the first time in nearly 50 years.
“Part of that work includes routine contingency planning for various scenarios that we don’t think will happen, but we have to be prepared for whatever happens.
“Whether we trade with the EU on terms similar to Canada or Australia, a brighter future awaits us as we forge our own course. ”
A government spokesperson added that “intensive planning is underway to help ensure that businesses and citizens are ready to take advantage of the opportunities and changes” that the exit from the single market and the Union customs union.
She continued, “As a responsible government, we continue to prepare intensively for a wide range of scenarios, including the reasonable worst-case scenario.
“This is not a forecast or prediction of what’s going to happen, but rather a scalable scenario.
“This reflects a responsible government that makes sure we are prepared for all eventualities. “