Hello, I'm Rahul Tandon. Welcome to Business Daily from the BBC. Coming up, it's a historic day for the UK's relationship with the European Union. After four years, the UK is officially out. We're going to hear a bit about how we got there, the abridged version at least.

We must build a kind of United States of Europe.

And then a look at the future.

Are we done with Brexit now, or is the adjustment period just going to continue?

There's this famous cartoon that came out.

My father was a Brexit negotiator just as his father before him.

And we laughed at it at

the time, but now it's not as funny anymore because it might actually be true. That's all coming up

in Business Daily from the BBC. As you've been hearing, the UK has formally separated from the EU

after technically leaving in January last year.

So how did we get there?

It's a complicated question,

and the BBC's Marie Keyworth volunteered to tackle it for us.

The story of EU and UK relations is a long and complicated one.

So to help tell it, I'm enlisting some help.

I'm Dr Tim Oliver. I'm a senior lecturer at Loughby University's London campus.

And I've worked on UK-E relations for most of my academic life.

Julie Smith, I'm reader in European politics at Cambridge University.

So Tim and Julie, let's start in the late 1940s.

Europe was at peace, but still reeling from the devastation of World War II.

For the United Kingdom, there was a sense that the future was one,

built on a strong relationship with the United States and with the Commonwealth,

...