London, February 1 (RHC)-- The flags outside embassies have been lowered, the countdown clocks have stopped. The United Kingdom is no longer a member of the European Union.  The country's 47 years of membership officially ended at the stroke of 12 midnight Brussels time, more than three and half years after an in/out referendum exposed deep rifts across British society.

While celebrations to mark "Brexit day" saw EU flags being burned on the streets of London, UK Prime Minister Boris Johnson marked the historic moment with his team at his Downing Street office, celebrating with English sparkling wine and an array of British culinary treats.

As the clock ticked down the final seconds, thousands of Brexiters partied outside Parliament, while anti-Brexit campaigners mounted several protests along the Irish border.

While Johnson must now achieve a trade deal within 11 months with the EU -- the world's largest trading bloc -- a task most experts have described as ambitious at best, his wider mission over the next five years will be to find a way to repair the country's divisions.

The years since the referendum have seen ugly scenes at protests and clashes between pro- and anti-Europe demonstrators, as well as bitter rhetoric dominating newspapers and appearing in Parliament.