Again: Calm down. This isn't comparable to Le pen, farage, Putin, Trump because it's 13%, not 50 or more.
Farage and UKIP only gained 12% of the national vote in the 2015 UK General election and never even managed to get a seat in Parliament. David Cameron saw their rise and hoped to neuter it with the EU referendum and gain a remain win but it backfired massively. These parties don't have to have a majority to do damage.