There could be food and medicine shortages, public disorder, and electricity price rises in the event of a no-deal Brexit.
Operation Yellowhammer is also warning of civil disobedience and road blockages near the Irish border.
The documents were released after opposition MPs defeated the UK government in the House of Commons to order their publication.
Labour now wants Parliament recalled in order to stop the UK leaving the EU without an agreement.
UK Defence Secretary Ben Wallace says the projections in the document are worst case scenarios.