Victoria Derbyshire

The nature of Brexit will ultimately be decided by the governments of the 27 remaining EU nations and the UK. But the figures who negotiate the detail of the deal will be hugely important.

Many would argue that Germany's Angela Merkel and the UK's Theresa May are the two most important people in the Brexit negotiations.

But there are eight figures who will also be crucial to what happens.

Of the four from the UK, three are within the Exiting the EU department. 

On the EU side, the figures represent the Commission (the EU's executive cabinet), the Council (the leaders of each member state) and the parliament of elected MEPs, who will have to approve the final deal. Read more about them

Katya Adler
Europe Editor

Image source, AP

Britain's Ambassador to the EU, Sir Tim Barrow - aka The Man with the Burning Letter in his Hand - arrived at the European Council Building without much fanfare this morning. 

Waiting journalists joked he may roll up in a red, white and blue mini to match Theresa May's promise of a red, white and blue Brexit .. but instead it was the usual shiny black jaguar. 

The eyes of Europe are on Sir Tim. This is not only an historic day for the UK, it's a momentous never-to-be forgotten kick in the stomach for the EU.

Kamal Ahmed
Economics editor

Image source, PA

The BBC's specialist editors have been considering how Brexit will affect their patches. 

Here are Kamal Ahmed's views on the implications for the British economy.

For the future of the economy, there are two intertwined issues at the top of the "importance" league table.

First, the type of trade deal Britain secures with the European Union following Brexit.

In economic terms, the more "frictionless" that relationship, the better.

Studies by the National Institute for Economic and Social Research suggest leaving the single market could lead to a long-term reduction in total UK trade with Europe of between 22% and 30%, unless Britain signs exactly the same free trade deal as it has now (which many in the EU have made clear they do not support).

That stark fall in trade - and therefore in the creation of growth and wealth in the economy - reflects the fact the single market is a comprehensive trade agreement aimed at reducing tariff barriers within the EU (the UK's largest export market).

But, as importantly, the single market also seeks to reduce "non-tariff barriers", the rules and regulations governing issues such as safety certification and licensing of goods and services provided across borders.

For an economy such as Britain's, driven by services such as retail and finance, non-tariff barriers are very important as well as very complicated.

The government believes some of that trade impact can be offset with new free trade deals with countries outside the EU, such as Canada and the US, but they may take a while.

Watch the detail closely - the UK's future trade deals will be key to the future performance of the economy. Read more

Image source, AFP

They say a week is a long time in politics but the next few hours could seem like an eternity for Sir Tim Barrow.

The UK's ambassador to the EU who has been entrusted with the Article 50 letter has already arrived at the European Council building but he is not due to hand over his precious cargo for almost three hours.

How will he fill his time? 

Presumably, that rather smart briefcase - which has the royal insignia ER on it - containing the letter will never be out of his hands, let alone his sight or will another official take over in the interim?

We are unlikely to learn the answer to these questions but we all know what can happen when envelopes and letters get mixed up. 

Just ask the producers and stars of La-La Land and Moonlight.

Let's just hope this all goes to plan. 

Image source, AFP

BBC Radio 5 live

With Article 50 approaching, is it time for Remainers to accept the Leave vote? Things got heated in the BBC Radio 5 live studio between one Leave voter and one Remain voter - who both had very different views. 

Yorkshire financial advisor Neil said "Remoaners" who were trying to keep Britain in the EU were committing "nothing short of treason". However, he was countered by Leeds student Lance who said he would not change his opinion when he "full heartedly" felt Brexit was wrong. 

You can listen to the full debate on BBC Radio 5 live Breakfast until 10:00 this morning.

Leaving cabinet, Boris Johnson - you can see him there behind the BBC's Norman Smith in Downing Street - has said today is "a great day, a historic day". 

Image source, EPA

Sir Tim Barrow has arrived at the European Council building in Brussels clutching a briefcase containing the Article 50 letter.

With a bank of cameras capturing the historic moment, the ambassador greeted reporters as he walked into the Europa Building in the heart of the European quarter, where he is expected to hand over the document this afternoon.

Apparently the letter was ferried across the channel yesterday on Eurostar, with a certain degree of security.

Today Programme
BBC Radio 4

Today Programme
BBC Radio 4

The cabinet is currently meeting, with presumably one subject on the agenda.

Here are a few images of ministers arriving earlier as well as a shot of one interested furry onlooker. 

Image source, Reuters

Image source, Reuters

Image source, Reuters

Image source, Reuters

Image source, Reuters

Wales' vote for Brexit left First Minister Carwyn Jones - a staunch Remainer - in a difficult situation.