After over three years of wrangling, UK officially leaves EU with deep impact both sides

The United Kingdom finally cast off from the European Union on Friday for an uncertain Brexit future, turning its back after 47 years on the post-World War Two project that sought to build the ruined nations of Europe into a global power.

In its biggest geopolitical shift since losing its global empire, the United Kingdom slipped away at 2300 GMT in a step cast by Prime Minister Boris Johnson as the dawn of new era.

Thousands of Brexit supporters gathered outside the British parliament, waving flags, singing and reveling in a mix of nostalgia, patriotism and defiance.

"This is a fantastic day," said Tony Williams, 53, from south-east London. "We are free, from 11 o'clock, we have done it … We have done it."

Brexit, once considered the unlikely dream of a motley crew of "eurosceptics" on the fringes of British politics, also weakens the EU, conceived as a way to bind together Europe's major powers in peace after centuries of conflict.

When the exit day finally came, after 3-1/2 years of wrangling since the 2016 referendum, it was an anticlimax of sorts: while Brexiteers waving flags toasted freedom in the rain, many Britons showed indifference or relief.

"For many people, this is an astonishing moment of hope, a moment they thought would never come," Johnson, the New York-born leader of the official "Leave" campaign, said in a pre-recorded address to the nation.

"Our job as the government — my job — is to bring this country together now and take us forward," said Johnson.

He celebrated in Downing Street with English sparkling wine and a distinctly British array of canapés including Shropshire blue cheese and Yorkshire puddings with beef and horseradish.

The EU's most powerful leaders, German Chancellor Angela...