The European Union has issued a 16-page document outlining the preparations that need to be made for Brexit. It includes advice on how countries, companies and individuals should prepare for the prospect of the UK leaving with "no deal" in place.
BBC Reality Check correspondent Chris Morris has read the document so you don't have to. Here are some key excerpts, and explanations of what they mean:
From the outset, the EU makes one thing clear - even if negotiations go better than expected, it thinks there will be significant disruption, and everyone needs to be ready for it. (The EU talks about 30 March as exit day, by the way, because the precise time of withdrawal is due to be midnight on 30 March in Central European Time, but 23:00 on 29 March in GMT).
The document emphasises that negotiations on a withdrawal agreement are continuing and that a negotiated settlement is the EU's preferred outcome.
But it also notes that important issues remain unresolved - including on the protection of personal data sent to the UK while it was a member state and on the role of the European Court of Justice (ECJ) in policing a withdrawal agreement.
In particular, it states that there has been "no progress" in agreeing a "backstop" solution to avoid the imposition of a hard border between Northern Ireland and the Republic of Ireland.
The EU notes, as it has done many times before, that time to both reach and ratify an agreement is running short.
This is why preparations for "no deal" are so important.
If there is a deal, there will also be a transition period running until 31 December 2020 during which EU rules and regulations will continue to apply in the UK.
That will give businesses and governments more time to prepare for a new relationship.
Without a deal, the transition (or "implementation period" as the UK government calls it) falls away and the relationship will change abruptly at the end of March next year.
If both sides come to the conclusion several months before the end of March that there will be "no deal", they can at least make some contingency plans to deal with that.
But if there is a last-minute hitch, time will have run out.
So, from the EU's perspective, thinking about "no deal" means "preparing for the worst and hoping for the best".
Much of the UK government would probably look at it in the same way - but there are many Brexiteers who think that "no deal" would be perfectly acceptable as long as sufficient preparations have been made.
Stepping up preparation
This kind of language is scattered throughout the document. "Don't say we didn't warn you," would be another way of putting it.
The document stresses that some things will have to be done whatever the outcome.
One thing it mentions is the need for companies to take steps to ensure that they have the right authorisations and certificates to access the EU market after Brexit.
But contingency planning for "no deal" is the main emphasis - the EU says this is a prudent step because the outcome of negotiations "cannot be predicted".
Among other issues, it notes that there would be no arrangement in place for EU citizens in the UK or UK citizens in the EU.
It says controls at borders "could cause significant delays, eg in road transport, and difficulties for ports", where there could be "long lines of vehicles waiting for customs procedures to be fulfilled".
It also says that the UK would become a third country for trade and regulatory issues, which would "represent a significant drawback compared to the current level of market integration".
It also emphasises that while many measures would have to be taken at EU level, national, regional and local governments also need to step up their levels of preparation to "mitigate the worst impacts of a potential cliff-edge scenario" - cheerful stuff.
And of course a lot of the attention is focused on making sure that individual EU businesses, big and small, are going to be ready for whatever emerges at the end of a highly unpredictable process of negotiation.
The document also claims - in a sentence that won't please the UK government - that "many companies are relocating to the EU27" or expanding their operations there.
EU officials insist that they are not trying to add fuel to the fire and that they are simply engaged in prudent planning.
But it's a reminder that there are people in Europe, as well as in the UK, who see Brexit as an opportunity rather than a threat.
Legal and technical implications
The commission has now published 68 notices (anyone with a few hours to spare can read them here) on preparations in specific sectors of the economy, including health and food safety, financial services, customs, transport, and company law.
They set out the legal and technical issues that governments and companies need to take into account and are another glimpse into the complexities of Brexit that stretch into every area of economic life.
In the UK, the government has not yet published any comparable information of its own.
However, on Wednesday, Theresa May told MPs at the Liaison Committee that a similar number of technical notifications about what to do in the event of a "no deal" Brexit will be released during August and September - aimed at businesses and citizens.
In response to the EU document, the Department for Exiting the European Union said "It is the duty of any responsible government to prepare for every eventuality, including the unlikely scenario that we reach March 2019 without agreeing a deal. We have already done a lot of work behind the scenes to prepare for this - it is only natural that our European partners would seek to make similar preparations. We are keen to work closely with the EU on preparedness issues."
Access to databases
There are all sorts of EU databases, including many dealing with policing and internal security issues, to which the UK wants to retain access after Brexit.
But the EU has argued that the UK can't simply pick and choose the bits of membership it likes - and this part of the document emphasises that work is well under way to remove the UK from numerous databases and IT systems once it becomes a "third country".
The commission is also making preparations for changing international agreements that currently involve the UK as a member state. It says it will notify its international partners formally once it has sufficient certainty about the outcome of the current negotiations - not for a while, then.
Finally, the EU document says work is under way to relocate or reassign tasks that are currently performed in the UK - such as the Galileo Security Monitoring Centre (part of the EU's project for satellites in space) or the UK-based EU Reference Laboratories - because it will not be possible "to entrust a third country" with such EU tasks after the withdrawal date.
Two London-based agencies, the European Medicines Agency and the European Banking Authority, are already moving to Amsterdam and Paris respectively.