And we're off! Despite the best efforts of the Negative Nellies, the hour has come.
Just over nine months since the United Kingdom voted to leave the European Union, we triggered Article 50. A letter from the government was delivered in person by Tim Barrow, the UK's permanent representative in Brussels, to the European Council president. A strangely old-fashioned touch, but one that reflects the historic nature of the occasion. It wouldn't do to send a text saying: "So long, farewell, auf wiedersehen, adieu." Tempting though that might be, especially if we could get Julie Andrews to sing it.
But what can you possibly say at the end of a 44-year relationship? There were 28 of us in this marriage; 27 will now be feeling upset, annoyed and even jealous. Some will look at our divorce to see if they, too, can resume life as an independent nation, while getting custody of the cat.
Let's imagine what the letter would say, if we decided to forego diplomatic niceties to tell the truth...
This is a letter for the European Union, but we are addressing it to you, for it is Brussels and its bureaucracy with which we are breaking, not Europe. The British people love Europe. We love the way it freed us from our grey, post-war gloom. We love Paris in the springtime and Venice in winter. We love Spain so much that 761,000 of us have made our lives there. We don't visit Germany as much, but those of us who remember the Austin Maestro thank Gott for its Polos, Golfs and BMWs.
Europe taught us how to eat; a generation that was raised on the Findus Crispy Pancake now feeds its own children pasta, garlic bread and fromage frais. The Mediterranean diet is best for the heart, just as Europe is good for the Anglo-Saxon soul. Without it, we would definitely be a sadder place with a vitamin D deficiency and, quite possibly, rickets. The UK will never fall out of love with Europe, but, sadly, our marriage with the EU became an abusive one. You changed. When we first got together in 1973, you were strong and capable of growth. Before long, though, we started to see signs of an unpleasant, controlling personality. You churned out miles - sorry, kilometres - of intrusive, often barmy regulations. And, because we are British, we obeyed them.
To take just one small example, we were told that universities within the EU must open jobs to academics from other member states. Only two nations succeeded to any serious extent: the Netherlands and the UK. Germany scarcely did. France reserved all her university positions for the French. Quelle surprise. Italy, meanwhile, kept it in the family - a startling number of professors shared the same surname. Those are basically the conclusions of a recent EU study, so we're not being paranoid. You made the rules, we played by them; others did not.
Your crazy over-regulation was symptomatic of a desire to create a European superstate while imposing your will on your subject peoples. How right Mikhail Gorbachev was when he said: "The most puzzling development in politics during the past decade is the apparent determination of Western European leaders to recreate the Soviet Union in Western Europe."
To advance your project, you introduced the euro, even though many economists predicted it would be a disaster. Imagine tying an Andalucian donkey cart to the bumper of a German Merc. Well, that's what you did. Over a quarter of young people in southern Europe are unemployed today because of your arrogance and stupidity.
Unlike any other trading bloc in the world, the EU made free movement of people a condition of membership. This caused huge pressure in the UK, which was a honeypot for migrants from Eastern Europe. Millions came and, astonishingly, you insisted that we had to send child benefit to their offspring in other countries, while we were cutting benefits at home.
Whenever a member state voted to reject further European integration, you either made them vote again or you got your way by bundling whatever measure they had turned down into a new treaty. As Jean-Claude Juncker, head of the European Commission, said of the 2005 French referendum on the Lisbon Treaty: "If it's a Yes, we will say 'on we go', and if it's a No, we will say 'we continue'." Well, now the UK has voted. The British people decided against a European superstate, against lack of democratic accountability, against a self-serving elite that would rather see Greeks and Spaniards eat dog than be deflected from its grand project. On June 23 2016, we voted to control our own borders and determine our own laws. Both legitimate aspirations which, if the EU had any sense, it would grant to all its member states.
Now the UK has given you notice that we are leaving the EU. We are the first, but almost certainly not the last. We hold no brief for Marine Le Pen, but she is riding high in the polls, and what she has told the French electorate may not be a hollow threat: "The EU will die because the people do not want it any more... arrogant and hegemonic empires are destined to perish."
We very much hope that negotiations over the next two years will be cordial and productive. The UK bears no ill will towards our European neighbours. On the contrary, we hope that both our trade and our friendships will go from strength to strength. We want your cheese, your cars and your prosecco as much as you need our world-class intelligence services and popular music.
Finally, about this exit bill. You want us to pay you €60 billion? Well, we did have a Diet Coke and Twix from the mini bar, but the kitchen was closed. Let's say 60 quid and no hard feelings?
The United Kingdom of Great Britain and Northern Ireland.
Allison Pearson is a columnist with the 'Daily Telegraph'