A no-deal Brexit could lead to outbreaks of disease and shortages of medicine, fresh food and fuel, with the poorest hit worst, official government documents show.
The papers – marked “official sensitive” – also warn of “a rise in public disorder and community tensions”, “panic buying” at supermarkets, and huge traffic jams in Kent as the EU imposes tariffs and checks on UK goods.
There are also likely to be delays for passengers at airports and ports as British citizens will face more stringent immigration checks.
The Operation Yellowhammer “reasonable worst case scenario” papers are dated August 2, after Boris Johnson became prime minister, and were released after his administration lost a Commons vote on Monday demanding publication.
A separate request to publish communications between officials about the controversial shutdown of parliament was rejected by the government, which argued its publication would break several laws.
The papers could put huge pressure on the prime minister to abandon his pledge to quit the EU, deal or no-deal, on October 31 – a promise is already running contrary to a law passed by MPs to block no-deal on Halloween.
Michael Gove, the cabinet minister in charge of no deal planning, insisted the Yellowhammer documents were not “a prediction of what is most likely to happen”.
“It describes what could occur in a reasonable worst case scenario, thus providing a deliberately stretching context for government planning to ensure that we are prepared for exit,” he said.
But Sunday Times journalist Rosamund Urwin, who obtained a near-identical leak of Yellowhammer documents last month, insisted the version she had was a “base scenario”, suggesting it indicated what was likely to happen.