BREAKING: Biden takes Pennsylvania and the presidency

By winning Pennsylvania, Joe Biden has won the vote to become the next president, according to a projection by BBC.

The projection of his win in the crucial state gave him 20 electoral college votes, bringing his total to 273 and surpassing the 270 needed to win the election.

Under the US system, voters in each state pick electors, who then gather a few weeks after the election to decide the winner.

Each elector equals one electoral vote, and the number of electoral votes per state is roughly in line with its population — so bigger states like Texas (38) and California (55) have more, while smaller states like Delaware (3) and Idaho (4) have fewer. In total there are 538 electoral votes, and a candidate needs 270 to win.

Pennsylvania was enough to get Biden over that halfway line. With leads in Georgia, Arizona and Nevada, he may well end up winning far more than needed — taking those three states would give him a total of 306. Joe Biden was spending the morning with his family at his home in Delaware when he saw the news that he was projected the winner of his native Pennsylvania and will be the 46th president of the United States.

He will address the nation tonight, an official told CNN.

A line from Biden’s speech last night will be a theme of his remarks: “Never forget: the tallies aren't just numbers. They represent votes and voters, men and women who exercise the fundamental right to have their voice heard.”

Before becoming the Democratic presidential nominee, Biden served as vice president under former President Barack Obama. He is also Delaware's longest-serving senator.

Throughout his campaign, Biden has argued that the "soul of the nation" is at stake, and has promised that he would seek to heal a country fractured by Trump's presidency.