How did the Sweden Democrats become the Riksdag's second-largest party?

In Sweden's 2006 election, the Sweden Democrats got barely 3% of the vote — but 20 years on they're the country's second-largest political party.

So how did the Sweden Democrats manage to grow so much, despite the party's far-right extremist origins?

Listen to hear Nicholas Aylott, a political scientist at Södertörn University, explain the party's history and where it sits on the political spectrum today. ...