The leaked Yellowhammer report, which warns of dire effects of a no-deal Brexit, was described as a “likely, basic, reasonable scenarios” and not “the worst case,” as Michael Gove has downplayed it.

The secret Whitehall dossier, which was leaked to the Sunday Times, raises the prospect of food, fuel, and medical shortages and a hard border with Ireland as some of the most likely aftershocks of leaving the EU without a deal.

A senior civil servant told the Sunday Times: "This is not Project Fear - this is the most realistic assessment of what the public face with no deal. These are likely, basic, reasonable scenarios - not the worst case."

But ministers Kwasi Karteng and Michael Gove went into damage limitation mode after the leak, attempting to play down fears as "scaremongering". Meanwhile, Tory former cabinet ministers Iain Duncan Smith and Owen Paterson claimed the leak was an example of the "establishment" plot to "sow fear in people's minds".

Business minister Kwarteng told Sky's Sophy Ridge on Sunday: "I think there is a lot of scaremongering around and a lot of people are playing into Project Fear and all the rest of it.

"We've got to prepare for no-deal. In fact the previous prime minister created DExEU and she said that the mandate of DExEU last year, last summer, was to prepare for no-deal...

"Now we've got a new prime minister who is very much focused on that and the scale and intensity of those preparations are increasing and we will be fully prepared to leave without a deal on October 31."

Gove, who as Chancellor of the Duchy of Lancaster is responsible for no-deal planning, tweeted: "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 three weeks to accelerate Brexit planning."

A Downing Street source claimed it had been leaked by a former minister.

According to the documents, petrol import tariffs would "inadvertently" lead to the closure of two oil refineries, while protests across the UK could "require significant amounts of police resources" in a no-deal scenario.

They predict the return of a hard border with Ireland, potentially sparking protests and direct action.

There are border delays predicted at the Channel crossing and at ports, with disruption at the latter lasting potentially three months. Eighty-five percent of lorries "may not be ready" for French customs.

Medical supplies would be "vulnerable to sever extended delays", and consumers may face price rises as the availability of fresh food is reduced.

This, along with rising costs of social care predicted within around six months for larger providers, would hit the poor hardest.

The report also warns that Gibraltar could face delays of up to four hours at the border with Spain for "at least a few months".

But the chief minister of Gibraltar said the Operation Yellowhammer documents were "out of date" and based on "planning for worst case scenarios".

Fabian Picardo said: "We do not want a no-deal Brexit. We think it is bad for Gibraltar. We are, nonetheless, now ready for it. The matters raised in the outdated Yellowhammer leak have already been responsibly addressed in detail."

A Number 10 source said: "This document is from when ministers were blocking what needed to be done to get ready to leave and the funds were not available. It has been deliberately leaked by a former minister in an attempt to influence discussions with EU leaders.

"Those obstructing preparation are no longer in government, £2 billion of extra funding already made available and Whitehall has been stood up to actually do the work through the daily ministerial meetings. The entire posture of government has changed."

However, the SNP's Stephen Gethins said the documents lay bare the "sheer havoc Scotland and the UK are hurtling towards".

"The Tory prime minister is in a state of delusion and denial over the impact his extreme Brexit plans will have on essential supplies such as food, medicines and fuel," he said.

"The worrying reality is that these internal government papers are only setting out the best-case scenario. It is clear that even in the face of disaster this Tory government simply plans to walk over the cliff-edge, dragging Scotland with it."

Liberal Democrat Brexit spokesperson Tom Brake said: "Operation Yellowhammer reveals the truth of a no-deal Brexit. It would have wartime implications, in peacetime, all of them self-inflicted.

"People will be horrified that Boris Johnson and the Conservatives are willing to pursue a plan that will lead to shortages of medicines, food and fuel. This is a far cry from the promises Boris Johnson made in the referendum campaign."

A Whitehall source told the Sunday Times: "We have lost our ability to communicate the truth to the public — anyone is not believed. We need to give people facts but it's so politically febrile that no one is doing that."