Brexit finally happens: The United Kingdom has left the European Union
- The United Kingdom has officially left the European Union.
- There were celebrations and protests nationwide as the UK counted down to Brexit at 11 pm (GMT.)
- The UK government projected a countdown clock onto Downing Street in the run-up to the moment.
- Prime Minister Boris Johnson welcomed a "new dawn" for the country.
- Visit Business Insider's homepage for more stories.
The United Kingdom has finally left the European Union, after three and a half years of political turmoil.
There were celebrations and protests across the country as the clock counted down to 11 pm (GMT) on Friday, bringing an end to almost half a century of Britain's membership of the EU.
In a speech broadcast on Facebook an hour before Britain's exit, Prime Minister Boris Johnson said the moment represented a "new dawn" for the country after three years of division, delay and parliamentary deadlock.
"The most important thing to say tonight is that this is not an end but a beginning," Johnson said in a video message filmed inside his 10 Downing Street residence.
"This is the moment when the dawn breaks and the curtain goes up on a new act.
"It is a moment of real national renewal and change."
The UK government projected a countdown clock onto the front of Downing Street in the hour leading up to 11 p.m., while Leave voters celebrated outside the Houses of Parliament with pro-Brexit politicians like Nigel Farage.
Britain formally left the EU hours after Johnson and his Cabinet met in Sunderland. This city in northeast England was famously the first area of the country to declare a Leave vote at the 2016 referendum.
This meeting of Johnson and his most senior ministers was designed as a public display the government's commitment to improve the lives of voters in Brexit-voting areas of the UK outside of London and the south-east of England.
Meanwhile, in Brussels, there were historic scenes as EU officials took down Union Jack flags in preparation for Britain's formal departure.
What will happen now Britain has left the EU?
The UK will now enter an 11-month transition period, during which it will continue to follow EU rules and laws.
This means life won't feel any different for UK citizens until January 2021, when the UK's relationship with the EU will change significantly.
In the meantime, the UK government plans to negotiate a new free trade deal with the EU, as well as free trade agreements with countries like the US, Japan, Australia, and New Zealand.
Georgina Wright, from the Westminster-based Institute for Government think tank, told Business Insider that negotiating a new trade deal with the EU will be the "greatest and arguably most complex negotiation" of the entire Brexit process.
"February 1 is the end of the beginning, it's not the beginning of the end," Wright said.
"The scale of the task is massive... If you look at how long other trade negotiations have taken, it's basically a couple of years [until a full deal is agreed], especially if you're looking at something very comprehensive."
Multiple senior EU figures have insisted that a deal will take much longer than the 11 months allowed by the transition period.
Johnson insists that he will not extend the transition period beyond December 2020. Experts have warned that this creates a new cliff-edge at the end of the year, in which the UK could switch to costly new trading terms with the EU.
Perhaps the most controversial element of the trade negotiations will be with Donald Trump's US, where issues such as food standards, pharmaceuticals, taxation on US tech firms, and vehicle tariffs will dominate.
How did we get here?
Cameron's failure to persuade the nation to stay in the EU triggered his resignation, and eventually led to his replacement by Theresa May.
However, May's decision in 2017 to hold a snap general election, in which she lost the Conservative party's majority in parliament, handed legislative power to opposition MPs, and left the UK in an extended period of political deadlock.
MPs rejected May's Brexit deal with the EU on numerous occasions, forcing her to delay Britain's exit twice.
May resigned as prime minister and Conservative party leader in 2019, triggering a leadership contest which Johnson went on to win convincingly, promising to deliver Brexit as soon as possible.
Despite Johnson's victory, MPs voted again to block a no-deal Brexit taking place in October, leading the new prime minister to seek a fresh delay to Britain's exit, pushing it back to January 2020.
Johnson then called a general election in which he successfully won an 80-seat majority, ensuring that Britain would finally leave the EU.