LONDON — The United Kingdom is headed for a general election less than two weeks before Christmas, the latest attempt to break the country's Brexit deadlock.

The House of Commons voted Tuesday night by 438 to 20 to hold the early vote on Dec. 12. It will be the country's third general election in less than five years and the first held in December in almost a century.

Although he runs the government and is leading in the polls, Prime Minister Boris Johnson does not have a majority in Parliament so he needed the support of the Labour Party to sign off on the plan.

It must now go to the unelected House of Lords where it is not expected to meet any serious opposition.

Johnson told lawmakers earlier Tuesday that an election was the only way "to break free from this impasse."

Whether an election will indeed be enough to break the paralysis, chaos and uncertainty that is gripping British politics remains to be seen. What's clear is the central campaign issue will be Brexit.

The prime minister says he wants to leave the E.U. as soon as possible and has negotiated his own divorce deal with European negotiators. However many people — including some within Johnson's own party — fear his plan is too hard line.

He was forced to make a major concession this week after failing to pass his deal in Parliament. This meant he broke his promise to leave the E.U. by the deadline of Oct. 31, instead having to ask for an extension of three months.

The Labour Party says it wants to negotiate its own deal and put this back to the people in a second referendum. Corbyn had previously resisted calls for an early election because he said it would allow Johnson to leave Europe without a deal — an extreme scenario that could trigger severe economic pain. A "no deal" Brexit can't happen now until next year at the earliest.

"Today, after much denial and much bluster by the prime minister, [a no-deal Brexit] is officially off the table, so this country can vote for the government that it deserves," Corbyn told Parliament on Tuesday.

Others such as the Liberal Democrats and Scottish Nationalist Party want to cancel Brexit altogether. While the Brexit Party, led by President Donald Trump ally Nigel Farage, is the political newcomer that might seek to flank the Conservatives from the populist right.

Johnson's Conservative Party leads the polls by as much as 16 percentage points.

"However, this is also a time of political volatility and uncertainty," said Ben Page, chief executive of the pollster Ipsos Mori. "Although the Conservatives are ahead, the percentage vote share in the national polls does not automatically lead to seats in the House of Commons."

That's because of the quirks of Britain's winner-takes-all electoral system. Parties usually focus on a small number of battleground areas to add to their traditional heartlands, ignoring the places where they have almost no chance of winning.

If either the Conservatives or Labour were to secure a decisive enough victory, this would in theory give them the green light to push ahead with their agenda on Brexit and other issues. However, another possibility is that the election would return a Parliament just as deadlocked as this one.

If no party wins more than 50 percent of seats, it results in what is known as a "hung Parliament." It's what happened in 2017 and 2010 and usually means parties have to form coalitions in order to govern.

British elections are usually held every five years and in spring or summer. If approved, this election would be the third inside five years, and the first held in December since 1923.