Downing Street has reacted with fury to the leak of an official document predicting that a no-deal Brexit would lead to food, medicine and petrol shortages, with No 10 sources blaming the disclosure on a hostile former minister intent on ruining Boris Johnson’s trip to see EU leaders this week.

The leaked document, detailing preparations under Operation Yellowhammer, argues that the most likely scenario is severe extended delays to medicine supplies and shortages of some fresh foods, combined with price rises, if there is a no-deal Brexit on 31 October.

It said there would be a return to a hard border on the island of Ireland before long and a “three-month meltdown” at ports unable to cope with extra checks. Protests could break out across the UK, requiring significant police intervention, and two oil refineries could close, with thousands of job losses, according to the documents.

Those campaigning against a no-deal Brexit said the official Cabinet Office document confirmed all the warnings about the risks of crashing out without an agreement. Tom Brake, a leading Liberal Democrat MP, said it revealed the truth that no deal would “have wartime implications, in peacetime, all of them self-inflicted”.

Now we know the cost of no deal, MPs must do whatever it takes | Matthew d’Ancona Read more

The Freight Transport Association (FTA) also reacted with alarm to the idea of fuel shortages in particular, saying these possibilities had not been conveyed to them by the government.

“This is the first time the industry is learning of any threat to fuel supplies – a particularly worrying situation, as this would affect the movement of goods across the country, not just to and from Europe, and could put jobs at risk throughout the sector which keeps Britain trading,” a spokeswoman said.

Jeremy Corbyn is to accuse Johnson in a speech on Monday of “provoking the crisis our country faces this autumn” because he wants to turn the UK into a US-style tax haven on the shores of Europe.

It is understood the Labour leader is ready to back the calls of more than 100 MPs for parliament to be recalled to debate the seriousness of the situation, after pledging last week to call a vote of confidence in Johnson’s leadership and seeking to build support to install himself as a caretaker prime minister until a general election can be held.

After the Yellowhammer report emerged, senior government figures moved to dispute it and dismiss its dire warnings. Michael Gove, the Cabinet Office minister in charge of no-deal planning, said the document showed “absolutely the worst case”, and it was an “old document” that did not reflect significant steps taken by Johnson’s administration over the last four weeks.

Speaking to Sky News, Kwasi Kwarteng, an energy minister, dismissed it as something with “a lot of scaremongering around and a lot of people are playing into Project Fear and all the rest of it”. The government of Gibraltar also claimed that predictions of queues of up to four hours at the border with Spain were “out of date” and based on “planning for worst-case scenarios”.

A No 10 source was even more critical, claiming the leak came from one of Theresa May’s former ministers in order to undermine Johnson’s trip to see Angela Merkel, the German chancellor, on Wednesday and Emmanuel Macron, the French president, on Thursday.

Despite the document, leaked to the Sunday Times, being dated to earlier this month when Johnson was already in post, the senior No 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, £2bn of extra funding has already been 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.”

Downing Street advisers are privately claiming that EU leaders will not offer any concessions towards a new deal unless they are sure that parliament is unable to block a no-deal Brexit. They are already setting the stage to blame former ministers working against no deal, such as Philip Hammond and Greg Clark, for any failure in EU negotiations.

However, Conservative rebels and opposition MPs working to stop a no-deal Brexit say Johnson has deliberately set the bar too high in his demands for the EU to scrap the backstop – the insurance mechanism to stop a hard border in Ireland.

At his meetings with Merkel and Macron, Johnson is expected to reiterate that he will only accept a new deal that abandons the backstop, over concerns that it could trap the UK indefinitely in a customs union.

With the EU collectively refusing to budge on the issue, No 10 is only expecting minimal discussion of Brexit with Merkel and Macron – more a restatement of each side’s existing positions.

Instead, discussions are expected to revolve around the agenda for next week’s G7 summit in Biarritz in France, on issues such as foreign policy and security issues, the global economy and trade, and the environment and biodiversity.

With no new deal in sight, Whitehall departments are increasingly making no deal their central scenario. Priti Patel, the home secretary, is understood to have sent some of her civil servants to Singapore to study their border model, as she wants free movement to end on the dot of 31 October.

May’s administration had planned to introduce an immigration bill to delay the end of free movement until new systems were in place, but Patel believes that it can be stopped with secondary legislation and new arrangements put in place in time.

EU citizens who are resident in the UK will be allowed to stay under the “settled status” scheme, but campaign groups are warning that some people may be left in a legal limbo, especially if they frequently travel between the UK and the EU.