This evening, Prime Minister Boris Johnson will be addressing the nation ahead of the exit in a pre-recorded speech.
The speech will mark the occasion of Britain leaving the EU and strike a positive note about the years ahead as Britain navigates a future independent of the union.
What time is the Brexit speech?
The PM’s speech will be aired at 22:00 GMT, exactly an hour prior to the UK’s official exit from the union.
What is the PM expected to say?
The PM is expected to strike a positive note about Brexit, calling it "the moment when the dawn breaks and the curtain goes up on a new act".
Boris Johnson is expected to talk about the future with positivity, promising to heal the divides which have emerged since the EU Referendum back in 2016.
Brexit will be described as “a moment of real national renewal and change”, with the PM promising “the dawn of a new era in which we no longer accept that your life chances - your family's life chances - should depend on which part of the country you grow up in."
Looking forward, he’ll call tonight’s exit from the union a “moment when we begin to unite and level up".
How can I watch it live?
BBC 1 will be airing the speech at 10pm in a news special hosted by Huw Edwards, while on ITV the coverage will be led by Tom Bradby from 10pm.
It is likely that the speech will also be live streamed by major media outlets online.
Unusually, the address was filmed by Downing Street. Traditionally, speeches by the PM have been recorded by one broadcaster then shared among a pool of television networks.
What else will happen on Brexit night?
Big Ben will not chime at 11pm, despite a high-profile campaign aimed at getting it to ring out the UK’s exit from the union.
Brexiteers are expected to gather in Parliament Square for a party led by Nigel Farage, while Downing Street will be illuminated with a light show and a new Brexit 50p will enter circulation.
Candlelit vigils are planned in various locations around Scotland as part of a message to the EU to keep a place for Scotland open.
What changes after tonight?
Though 31 January is being marked as “Brexit Day”, once the clock strikes 11pm Britain will enter a transition period, with major changes not taking force until the end of December 2020.
This means many EU laws - such as the free movement of people - will stay in place until 2021.
The exit date was supposed to have taken place on 29 March 2019, but Brexit was delayed after MPs rejected a withdrawal agreement drawn up between former PM Theresa May and the EU.
The UK aims to have reached a permanent free trade agreement with the EU by the end of the transition period in late 2020.