The government’s preparations for a no-deal Brexit, known as Operation Yellowhammer, include warnings about the disruption to cross-Channel trade by the sudden ending of the European Union customs regulations.
The document says: “There is a risk panic buying will cause or exacerbate food supply disruption” and points out: “Low-income groups will be disproportionately affected by any price rises in food and fuel.”
In 2016 UK citizens in a referendum voted to leave the European Union.
The country was initially set to withdraw from the bloc in March 2019 but MPs voted down the Brexit deal negotiated by Theresa May and the deadline was moved to 31 October.
When Boris Johnson became Prime Minister in July he vowed to get Britain out of the EU by 31 October “with or without a deal.”
Critics say he has made no attempt to renegotiate Mrs May’s deal and opposition MPs say he is simply planning to crash out with no deal.
The Yellowhammer documents presume 31 October will be the date of a no-deal Brexit - despite Labour's insistence they will force Mr Johnson to ask for an extension - and point out because that day is a Thursday the first day when the consequences will be felt will be Friday 1 November which is “not to our advantage.”
Britain will be relegated to “third country status”, on a par with countries like Norway and Iceland.
The document says: “France will impose EU mandatory controls on UK goods from Day 1 No Deal (D1ND)…between 50-85 percent of HGVs travelling via the short Channel straits may not be ready for French customs.”
Trucks which are not ready for the new customs regime could end up blocking ports like Dover and Ramsgate and there would be a knock-on effect on motorways in Kent. The document warns this could last for at least three months.
The Yellowhammer documents, which were drawn up last month, have formed the basis of the government’s no-deal planning.
With the EU’s Common Fisheries Policy no longer applying to the UK, the document also raises the spectre of a new “cod war” - the clashes in the 1970s between British and Icelandic navy gunboats backing fishermen from their respective countries.
It says: “Up to 282 EU and EEA nations fishing vessels could enter illegally, or already be fishing in UK waters…on day one. This is likely to cause anger and frustration in the UK catching sector, which could lead to both clashes between fishing vessels and an increase in the non-compliance in the domestic fleet.”
It adds: “Competing demands on UK government and DA maritime agencies and their assets could put enforcement and response capabilities at risk, especially in the event of concurrent or cumulative incidents, which are likely to include illegal fishing, borders violations (smuggling and illegal migration) and any disorder or criminality arising as a result, eg violent disputes or blockading of ports.”
Yellowhammer predicts: “Protests and counter-protests will take place across the UK."
It also says: “Law enforcement data and information sharing between UK and EU will be disrupted.”
In February the National Police Chiefs' Council lead for Brexit, Deputy Assistant Commissioner Richard Martin, said British police officers and their European counterparts were dreading a no-deal Brexit.
He said one of the biggest worries was that British police forces would no longer have access to the Schengen Information System - a criminal database - and he said Britain would be "less safe" in the event of no-deal.
Mr Martin also said the EU arrest warrant system would be suspended, making it harder for Britain to get fugitives who fled to the European mainland or the Republic of Ireland.
Parliament has been suspended by Mr Johnson - who has denied claims he lied to the Queen in order to get her to sign off on the prorogation - and he is pushing for a general election to resolve the impasse.
His opponents say they will let him call an election only once the threat of a no-deal exit is taken off the table.
Michael Gove, the cabinet minister responsible for no-deal preparations, said the assumptions in the Yellowhammer document were being reviewed.
The document says: "Some cross-border UK financial services will be disrupted. Law enforcement data and information sharing between UK and EU will be disrupted. UK nationals will lose their EU citizenship and, as a result, can expect to lose associated rights and access to services over time, or be required to access them on a different basis to now."
It warns British citizens travelling to and from the EU may be subject to increased immigration checks.
While the demand for energy and water “will be met” and the government expects no disruption to electricity or gas interconnections, the availability of certain types of foodstuffs will decrease.
One part of the document - Article 15 - remains classified.