No-deal Brexit may spark 'consumer panic', food shortages and security threats within a fortnight, according to leaked Government document

Boris Johnson, pictured in London on Wednesday, has pledged to leave the EU on October 31 with or without a deal (Picture: Simon Dawson/EPA)

A no-deal Brexit could spark food shortages, "consumer panic" and increased threats to security in as little as two weeks, warns a leaked Government document.

With the pound potentially plummeting, security "gaps" could emerge within the first month, according to the presentation slide prepared for ministers and obtained by Sky News.

UK nationals in the European Union could meanwhile be stripped of their residence rights and access to services within a mere 24 hours, it warned.

There could also be "friction at sea" between EU and UK fishing vessels, it said.

Marked "official sensitive" and titled "What this could look like on the ground", the briefing emerged as Boris Johnson's new Government ramped up pledges to Brexit by October 31 with or without a deal.

Chancellor of the Exchequer Sajid Javid pledged to double spending on preparations for no-deal Brexit (PA)

On Thursday, Chancellor Sajid Javid announced £2.1 billion in funding to prepare for a no-deal scenario.

Bank of England governor Mark Carney has also warned that a no-deal Brexit would slam the UK economy with an "instantaneous shock", sending the pound sinking as inflation rises and GDP slows.

A second leaked document, this one from the Cabinet Office and seen by The Guardian, warned of potential "panic buying" which would worsen disruption to food supply and raise the risk of civil disorder.

Mark Carney acknowledged that 'in the event of a no-deal Brexit, the sterling exchange rate would probably fall, CPI inflation rise and GDP growth slow' (REUTERS)

Sky reported that its leaked slide was prepared in the final weeks of Theresa May's tenure as prime minister.

It is understood the document was shown to ministers but not signed off by the Government, meaning it was not official policy.

But the worst case scenarios - broken down into first day, first fortnight and first month categories - also included potential friction at sea between UK and EU fishing vessels.

Within 24 hours, it says cross-border agriculture trade in Northern Ireland "virtually stops" as other trade "slows".

In the first fortnight column, it details: "Potential consumer panic and food shortages, even in areas which are not directly affected at the border."

It also warns of a "possible increased risk of serious organised crime including people smuggling and illegal migration".

The first month could also see heightened policing resources becoming "unsustainable", as operational gaps in security "continue to emerge".

A No 10 spokeswoman said: "We do not comment on leaked documents."