LONDON — Secret British government documents have warned of serious disruptions across the country in the event that the U.K. leaves the European Union without a trade deal on Oct. 31, according to The Sunday Times.

The newspaper published what it said were three pages worth of "planning assumptions" detailing what the British government expects in the case of a sudden, "no-deal" exit from the E.U.

Among the most serious: "significant" disruptions to the supply of drugs and medicine, a decrease in the availability of fresh food and even potential fresh water shortages due to possible interruptions of imported water treatment chemicals.

Although the grim scenarios reportedly outlined in the government documents have long been floated by academics and economists, they've been repeatedly dismissed as scaremongering by proponents of Britain's departure from the bloc.

British Prime Minister Boris Johnson has said he is ready to leave the E.U. regardless of whether he is able to renegotiate the exit Brexit deal struck with Brussels by his predecessor, Theresa May.

His own officials, however, have warned that with a no-deal Brexit, the sharing of law enforcement data and the health of Britain's crucial financial services industry could be in jeopardy after Oct. 31.

Setting out a vision of jammed ports, public protests and widespread disruption, the Times said the forecasts compiled by the Cabinet Office set out the most likely aftershocks of a no-deal Brexit rather than the worst case scenarios.

But Michael Gove, the minister in charge of coordinating no-deal preparations, challenged that, saying that the documents did set out a worst case scenario and that planning had been accelerated in the last three weeks.

We don’t normally comment on leaks - but a few facts - Yellowhammer is a worst case scenario - v significant steps have been taken in the last 3 weeks to accelerate Brexit planning - and Black Swan is not an HMG doc but a film about a ballet dancer... https://t.co/lRAgavfDze — Michael Gove (@michaelgove) August 18, 2019

The Sunday Times did not explain how it got the documents. Britain's Cabinet Office declined an NBC News request for comment.

Johnson will this week tell French President Emmanuel Macron and German Chancellor Angela Merkel that the Westminster parliament cannot stop Brexit and a new deal must be agreed if Britain is to avoid leaving the E.U. without one.

The prime minister is coming under pressure from politicians across the political spectrum to prevent a disorderly departure, with opposition leader Jeremy Corbyn vowing this week to bring down Johnson's government in early September to delay Brexit.

It is, however, unclear if lawmakers have the unity or power to use the British parliament to prevent a no-deal departure — likely to be the United Kingdom's most significant move since World War Two.