As things stand, by law the United Kingdom is due to leave the European Union on 29 March, with or without a divorce agreement.
British Prime Minister Theresa May has been forced to shift position on Brexit, opening the door to a potential delay in the face of intense parliamentary opposition to a "no deal".
However, the government has refused to rule out such a scenario, and even a potential extension to the process brings no guarantee that the deadlock on the substantive issues will be broken. Recent talks between London and Brussels have failed to bear fruit following MPs’ rejection of the original withdrawal agreement.
A UK exit from the EU with no deal on the terms would hit more than trade – legal arrangements covering many aspects of everyday life would abruptly cease to apply.
Preparations for a no-deal scenario have intensified – as have business warnings of damaging consequences, dismissed as scare stories by some Brexit supporters.
Euronews has examined in detail how the rules would change under no-deal, and how this might affect the UK and the EU. Articles are clickable in the sections below.
Our explainer on trade looks at the potential impact of WTO rules and warnings of disruption to the economy on both sides of the English Channel.
We examine how EU citizens living in the UK and British nationals on the continent would be affected by a no-deal Brexit.
Travel and consumer issues
What no-deal would mean for travellers and consumers, covering issues such as passports and visas, health cover, driving, roaming charges, and cross-border legal cases.
The Irish border
Ireland insists the new EU-UK land border will remain open even under no deal, though the EU will want to protect its single market. Our overall Brexit Guide explains the controversial backstop proposal, while other explainers look at the historical context, and possible technological solutions and other alternative arrangements for the border.
The European Commission’s Contingency Action Plan for Brexit lays out basic plans in a no-deal scenario to regulate citizens’ rights, financial services, air transport, road haulage, customs and exports, and climate policy.
It does not cover issues such as cooperation on security, crime and terrorism. However, a British government paper makes it clear that the UK would no longer have a formal relationship with Europol, and would no longer be part of existing systems on data-sharing, extradition, and co-operating to fight money-laundering and terrorist financing. The UK's security minister has warned that both sides would be put at greater risk.
For scientific research, the British government has guaranteed funding for UK competitive bids for EU projects submitted before Brexit. But there is uncertainty over future partnerships beyond Horizon 2020, the EU research and innovation programme, when it ends next year. The government says it wants talks with the EU to ensure the UK can continue taking part in programmes as a third country.
The UK government has also published a series of papers giving advice on the consequences of no-deal and how to prepare. It confirms that there would be no agreement on applying arrangements set out in the exit deal.