Today is likely to go down in history. Prime Minister Theresa May has triggered Article 50 to officially begin the Brexit process.
Here's everything you need to know.
What is Article 50?
Article 50 refers to the 264-word clause of the Treaty on European Union (often referred to by the marginally more memorable moniker, the Lisbon Treaty) allowing countries to leave the European Union (EU).
Any country can leave the union subject to “its own constitutional requirements".
How do we leave?
The short word count does not give much in the way of detail.
The important parts are: We “shall notify the European Council”. Then comes the negotiation of the Council and the leaving country, “setting out the arrangements for its withdrawal, taking account of the framework for its future relationship with the Union.”
After that any deal will have to be ratified by the European Parliament.
What has happened so far today?
The cabinet met this morning to allow for Theresa May's top ministers to discuss the Article 50 notification.
Then, the Prime Minister faced her standard Wednesday grilling in the House of Commons at midday. As May made a statement to the house on the Brexit process after Prime Minister's Questions concluded, the Article 50 triggering was left unmentioned.
During PMQs, the notification to the European Council took place at around 12:20pm.
So how did the UK notify Europe?
While there is no stipulation in the article for the form the notification should take, a cheeky Whatsapp message would not meet the standard for statecraft required.
Instead, the UK’s ambassador to the EU, Sir Tim Barrow, hand-delivered the notification letter to the European Council and its president, Donald Tusk. The letter has been signed by the Prime Minister.
What is in the letter?
The letter has now been delivered, opened and read by Donald Tusk.
How long will negotiations last?
From the notification date the UK will have two years to negotiate the terms of exit.
The negotiations will follow the path set down by another article in a connected Treaty. The next bit of obscure constitutional jargon we will all need is Article 218(3) of the Treaty on the Functioning of the European Union.
This one is less important though: it just says the European Council must authorise the opening of negotiations and appoint a negotiator.
April and May will probably be dominated by the release of position papers laying out the negotiating stances of the UK and EU. Proper negotiations will then likely begin over the summer.
When will the UK officially leave the EU?
If this process is followed correctly the UK will have left the EU officially by the start of April 2019.
Whether this happens in practice might be rather more complicated. The vast body of EU law and regulations (not to mention the institutions which do the regulating) will probably take a significant amount of time to duplicate or remove.
Transitional deals around the UK’s leaving process have been called for in some quarters of the business community, although so far we have no detail on what the government’s priorities will be.
How will negotiations work?
The simple answer is that we do not really know. The process is unprecedented; no country has ever left the EU before. The European Council must authorise the opening of negotiations and appoint a negotiator.
The man tasked with representing the EU is Frenchman Michel Barnier.
Who will lead negotiations for the UK?
The UK’s negotiations will probably be led by the Prime Minister, with the Department for Exiting the European Union taking a big role. David Davis is the minister in charge. He has previously locked horns with Barnier when both served as Europe ministers. Davis is likely to be assisted by foreign secretary Boris Johnson.
Liam Fox, minister for international trade, may have some input. Also key will be Barrow, and the Brexit department’s top civil servant, Oliver Robbins.
Are firms ready?
Levels of preparation vary massively. Over two-thirds (69 per cent) of financial services firms are yet to publicly utter a word about how Brexit will affect them, despite the vote having taken place more than nine months ago, a survey has found.
Of the 222 companies tracked by professional services firm EY, only 23 per cent have declared that they will be moving some of their staff or operations away from the UK or that they are rethinking where their business should be domiciled.
Meanwhile, seven per cent have stated their commitment to keeping their operations in the UK.
What do businesses want?
The British Chambers of Commerce said yesterday: “Now that Brexit negotiations are set to begin. Businesses across the UK and their trading partners in Europe want answers to practical questions, not political posturing.”