This article has been updated.
By law, the United Kingdom is due to leave the European Union at the end of the Article 50 process, with or without a divorce agreement. The scheduled departure date is now October 31, 2019.
Leaders of the other 27 EU member states twice granted the UK an extension to the Brexit process, following a period of turmoil in the British parliament, which repeatedly rejected an exit deal with the bloc.
The agreement, on the terms of the UK’s exit and outlining a framework for future ties, had been negotiated by London and Brussels and approved by the 27 other EU governments.
The prospect of a "no deal" Brexit looms larger now that the UK has a new prime minister. Upon taking office, Boris Johnson immediately signalled his new government's determination to pull the UK out of the EU in the autumn, with or without a deal.
Meanwhile in Europe, there has been growing reluctance to let the UK's Brexit paralysis drag on and another extension to the process is far from certain.
A UK departure from the EU with no deal on the exit 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 are being revived – as are 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 and Customs Union. The government in Dublin will need to decide how to reconcile its obligations to the EU with its pledge not to introduce a hard border.
Our overall Brexit Guide explains the controversial backstop plan in the negotiated Withdrawal Agreement, while another backstop explainer considers Boris Johnson's opposition to it. 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 published when Theresa May was in office 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 then security minister 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.
Getting ready for no deal
The May government also published a series of papers giving advice to British citizens and businesses 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.
In August 2019, after the Bank of England lowered its growth forecast for the UK post-Brexit, its governor Mark Carney warned that in the event of no deal the economy would suffer an instant hit, prices would rise and the pound would fall, and even large profitable industries would become "uneconomic".
Government documents leaked to a Sunday newspaper, based on the government's preparations for a no-deal Brexit and codenamed "Operation Yellowhammer", contained warnings of possible food, medicine and fuel shortages.
In April 2019 a leaked letter by the government's most senior civil servant warned of an economic recession, food price rises, a severe impact on Britain's security services, police forces and legal system, and a return to direct rule by the UK government in Northern Ireland.
In June, the same civil servant, Sir Mark Sedwill, said government and public services were in "pretty good shape" to cope with a no-deal Brexit at the end of October. He added that in the private sector the level of preparedness varied from sector to sector.
In its June update on the state of contingency preparations across the EU, the European Commission concluded that they remained "adequate and fit for purpose".
In July the British employers' organisation the Confederation for British Industry (CBI) argued otherwise, its report saying that neither the UK nor the EU was ready for no deal.
The UK Institute for Government has assessed various EU countries' preparations for no deal. A later report by the institute warned that a no-deal Brexit would drain resources and dominate UK government business for years to come.