Yesterday, student Mhairi Black won a seat in Parliament, becoming the UK’s youngest lawmaker since the 1600s and defeating a career politician as part of a sweeping rejection of the Labour party.

Black, who belongs to the Scottish National Party, won the seat of Paisley and Renfrewshire South, beating the Labour party’s Douglas Alexander, who, at 47, is more than twice her age. Alexander had held the seat for 18 years and was a high-ranking figure in the Labour party, serving as Labour’s foreign policy spokesman and its general election campaign chief.

With her surprising upset victory, Black will become the UK’s youngest MP in almost 350 years, since Christopher Monck joined the House of Commons in 1667 at age 13. By beating incumbent Alexander by more than 6,000 votes, Black marked one of the biggest upsets in what has been overall an unpredictable general election.

“The people of Scotland are speaking and its time for their voice to be heard at Westminster,” Black said after her victory became official.

Under previous rules, Black would not have been eligible to run, but a 2006 law that lowered the age of eligibility for parliamentary candidates from 21 to 18 cleared the way for last night’s shocking win.

Serving in Parliament won’t be the only responsibility for Black in the coming year, however. She still has to take the final exams to complete her politics degree at Glasgow University.

As recently as last year, few would have predicted that anyone – much less a 20-year-old student from a working-class family – could have defeated Alexander, who held a majority margin of 16,000 votes. However, political engagement and support for the SNP grew in the leadup to last year’s independence referendum in Scotland, and many voters have become disillusioned with the representatives currently in power.

“People are engaged with politics again, they aren’t afraid to come up and ask the difficult questions,” Black told the Paisley Daily Express earlier this week.  “When we go out, we don’t even need to move – people are just coming up to us. They want a change and they see a vote the SNP as the only way to combat Westminster’s austerity agenda.”

Prone to the occasional curse and a few choice tweets discussing her nights out drinking, Black has already earned a reputation as a bit of an unconventional “firebrand” – as well as inexperienced, as her opponents have pointed out. Her win over the Labour stalwart may say more about the direction the political winds are blowing in Scotland than her individual skills or talent as a candidate.

Black’s victory is just one of the most high-profile in a stunning SNP sweep of the polls. The nationalist party, which supports independence for Scotland, has won 56 of Scotland’s 59 seats – taking many of them from Labour. Prior to the election, the SNP had only six seats.

“This of course has been a very difficult night for Labour,” said Alexander after the result was called.

“Scotland has chosen to oppose this Conservative government, but not place that trust in the Labour party. It will be our responsibility to re-win that trust in the months and years ahead.”

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