The government has released its latest batch of documents covering the potential effects of such a scenario, covering areas like consumer rights, rail transport, copyright and free trade.
On rail transport, the government says it would have to negotiate new arrangements with individual countries to keep trains heading to the continent.
“Arrangements for cross-border services would be subject to any bilateral arrangements that the UK negotiates with individual EU countries,” the technical notice said.
Sky News understands work to prepare for such a scenario is already under way, while Brexit Secretary Dominic Raab has said he is confident Britain would be able to negotiate such agreements with the likes of France, Belgium and the Netherlands.
Mr Raab said: “We’re confident we will have continuity on Eurostar, even in the worst case scenario of a “no deal” situation.
“We are working, not just with the domestic preparations we need to do, but with the Belgians, the Dutch and the French to make sure that not just passengers going on holiday, but also goods can continue to flow.”
Passengers have also been warned they will be responsible for ensuring their tickets are “sufficient to cover possible disruption”.
The guidance means some passengers may be tempted to buy more expensive amendable fares rather than fixed tickets, which are cheaper.
One paper covering copyright reveals Britons could be barred from accessing Netflix, Spotify and other online entertainment while travelling to EU states.
Under EU rules agreed in 2017, citizens can access accounts set up and based in one country while visiting other member states, although this regulation would cease to apply in the event of no deal.
The documents also reveal that under a no deal scenario:
:: Northern Ireland faces the threat of power blackouts as laws which cover the trade of electricity with the Republic would cease to exist;
:: Britain would lose free trade agreement with more than 70 non-EU countries around the world;
:: Breeders of pedigree horses, cattle, sheep, pigs and goats will lose their automatic recognition in the EU;
:: Imported caviar and fashion items made from certain animals skins could become more expensive.
Brexit Secretary Dominic Raab said: “We have now published over 100 technical notices, giving individuals, businesses, public bodies and NGOs (non-governmental organisations) information and guidance in the unlikely event of no deal.
“Securing a good deal with our EU partners remains our top priority.
“But, if the EU doesn’t match the ambition and pragmatism we’ve shown, we have the plans in place to avoid, mitigate or manage the risk of no deal – and make a success of Brexit.”
Labour’s Sir Keir Starmer said the government’s planning “won’t reassure anyone”.
The shadow Brexit secretary said: “Ministers have barely scratched the surface of what would need to be done in the event of the UK crashing out of the EU without a deal.
“Despite all the so-called no deal planning, the Government has yet to admit that a no deal would require a raft of substantial legislation to be rushed through Parliament, crucial stop gap agreements with the EU on matters relating to Northern Ireland and security, and the recruitment of thousands of custom officials.
“None of this is going to be done or ready by March 2019.”